Download Ribosylation of bovine serum albumin induces ROS accumulation

Eur Biophys J
DOI 10.1007/s00249-013-0929-6
ORIGINAL PAPER
Ribosylation of bovine serum albumin induces ROS accumulation
and cell death in cancer line (MCF-7)
Mohd Shahnawaz Khan • Sourabh Dwivedi • Medha Priyadarshini •
Shams Tabrez • Maqsood Ahmed Siddiqui • Haseeb Jagirdar •
Abdulrahman M. Al-Senaidy • Abdulaziz A. Al-Khedhairy • Javed Musarrat
Received: 28 April 2013 / Revised: 30 July 2013 / Accepted: 10 September 2013
Ó European Biophysical Societies’ Association 2013
Abstract Formation of advanced glycation end products
(AGE) is crucially involved in the several pathophysiologies
associated with ageing and diabetes, for example arthritis,
atherosclerosis, chronic renal insufficiency, Alzheimer’s
disease, nephropathy, neuropathy, and cataracts. Because of
devastating effects of AGE and the significance of bovine
serum albumin (BSA) as a transport protein, this study was
designed to investigate glycation-induced structural modifications in BSA and their functional consequences in breast
cancer cell line (MCF-7). We incubated D-ribose with BSA
and monitored formation of D-ribose-glycated BSA by
observing changes in the intensity of fluorescence at 410 nm.
NBT (nitro blue tetrazolium) assay was performed to confirm formation of keto-amine during glycation. Absorbance
at 540 nm (fructosamine) increased markedly with time.
Furthermore, intrinsic protein and 8-anilino-1-naphthalenesulfonate
(ANS)
fluorescence
revealed
marked
conformational changes in BSA upon ribosylation. In addition, a fluorescence assay with thioflavin T (ThT) revealed a
remarkable increase in fluorescence at 485 nm in the presence of glycated BSA. This suggests that glycation with Dribose induced aggregation of BSA into amyloid-like
deposits. Circular dichroism (CD) study of native and ribosylated BSA revealed molten globule formation in the
glycation pathway of BSA. Functional consequences of ribosylated BSA on cancer cell line, MCF-7 was studied by
MTT assay and ROS estimation. The results revealed cytotoxicity of ribosylated BSA on MCF-7 cells.
M. S. Khan (&) H. Jagirdar A. M. Al-Senaidy
Department of Biochemistry, College of Science, King Saud
University, Riyadh, Kingdom of Saudi Arabia
e-mail: [email protected]
Non-enzymatic glycation is a complex cascade of reactions
initiated by condensation of reducing sugars with the free
amino groups of proteins to form reversible Schiff’s bases
which undergo rearrangement to form relatively stable
Amadori products. Amadori products, over a period of time,
undergo a series of reactions involving multiple dehydration,
fragmentation, and oxidative modification via highly reactive dicarbonyl intermediates to form stable, heterogeneous
adducts called advanced glycation end products (AGE) (Sing
et al. 2001; Baynes et al. 1989; Monnier 1989).
Although AGE formation occurs during the normal
ageing process, it is accelerated under hyperglycemic
conditions. Further, it has been shown that formation of
AGE in vivo contributes to several pathophysiologies
associated with ageing and diabetes mellitus, for example
arthritis, atherosclerosis, chronic renal insufficiency, Alzheimer’s disease, nephropathy, neuropathy, and cataracts
S. Dwivedi M. A. Siddiqui A. A. Al-Khedhairy
DNA Research Chair, Department of Zoology, King Saud
University, Riyadh, Kingdom of Saudi Arabia
M. Priyadarshini
Department of Medicine, Division of Endocrinology,
Metabolism and Molecular Medicine, Northwestern University
Feinberg School of Medicine, Chicago, IL 60611, USA
S. Tabrez
King Fahd Medical Research Center, King Abdulaziz
University, P.O. Box 80216, Jeddah 21589, Saudi Arabia
J. Musarrat
Department of Agricultural Microbiology, Aligarh Muslim
University, Aligarh, India
Keywords Glycation Bovine serum albumin Cytotoxicity Fluorescence Circular dichroism
Introduction
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Eur Biophys J
(Vlassara 1996; Lyons et al. 1991; Brownlee 1995; Shuvaev et al. 2001; Luthra and Balasubramanian 1993;
Kumar et al. 2004). In addition, many cells have receptors
for AGE (RAGE). Interaction of AGE with RAGE leads to
activation of NF-kB, which stimulates generation of the
pro-inflammatory and adhesion molecules that underlie the
pathology of diabetic vascular complications (Mrudula
et al. 2007; Bengmark 2007). Moreover, abnormal modification, including glycation, induces neuronal proteins to
misfold and form amyloid fibrils in a stepwise process from
prefibrils to fibrils (Necula and Kuret 2004).
Glycation alters the biological activity of proteins and
degradation mechanisms. Protein cross-linking by glycation results in the formation of detergent-insoluble and
protease-resistant aggregates. Therefore, the study of
AGEs has become an important area of biomedical
research. Although much work has been conducted on
glycation of proteins with glucose, few research groups
have attempted to study glycation by ribose and resulting
effects on cell structure and function (Chanshuai et al.
2011). In recent years, ribosylation has attracted more
attention because of its involvement in protein glycation
and its subsequent effects, for example protein aggregation and production of reactive oxygen species (ROS)
(Zhang et al. 2006; Li et al. 2007; Tan et al. 2007; Yan
et al. 2012; Chen et al. 2009).
D-Ribose is present in living cells and is important in life
processes. It is the structural backbone of purines and
pyrimidines, critical cellular compounds which are components of genetic material, and is a constituent of
numerous cofactors, some vitamins, and adenosine triphosphate (ATP) the ‘‘energy currency’’ of the cell.
Importantly, every cell needs D-ribose for essential activity.
Levels of D-ribose in the blood and cerebrospinal fluid are
0.01–0.1 mM in healthy individuals (Seuffer 1977; Cai
et al. 2005). Also, endogenous D-ribose can be produced
from glucose via the hexose monophosphate shunt and is
released from nucleotides during metabolic turnover.
Although high levels of ribose have not been found in
common diseases, according to van der Knaap et al. (1999)
and Huck et al. (2004) a rare disease called ribose-5phosphate isomerase deficiency results in an increase in the
polyols arabitol, ribitol, and erithrol, with white matter
disorder. Furthermore, it has been reported that poly(ADPribosyl)ation of nuclear protein increases in Alzheimer’s
disease (Love et al. 1999).
Serum albumin comprises approximately 60 % of
human plasma protein and its concentration is the major
contributor to the oncotic pressure of blood. It is particularly sensitive to glycation. Marked structural and functional changes occur in BSA upon glycation. In vivo, the
proportion of glycated albumin in healthy persons is in the
range between 1 and 10 % (Shaklai et al. 1984; Peters
123
1996). However, among individuals with hyperglycemia it
can increase two to threefold (Woodside et al. 1998;
Bourdon et al. 1999). For this reason serum albumin has
been adopted as a model in many in-vitro studies on glycation (Syrovy 1994; Culbertson et al. 2003). Here we
investigate ribosylation induced structural modifications in
BSA and its resultant effects on MCF-7 cells.
Materials and methods
The reducing monosaccharide ribose was purchased from
Amresco (USA). BSA, thioflavin T, and MTT dye were
from Sigma (USA) and Aldrich (USA). Other chemicals
were of analytical grade.
Glycation of bovine serum albumin (BSA)
BSA was dissolved in phosphate-buffered-saline (pH 7.4)
to yield 100 mg/ml stock solution. This solution was then
mixed with ribose prepared in PBS (pH 7.4) to a final
concentration of 50 mg/ml BSA and 1 M ribose. BSA
alone and in the presence of ribose was used as control.
Reaction mixtures were incubated at 37 °C for 0–21 days.
All solutions were filtered through 0.22 lm membranes
(Millipore, USA).
Characterization of ribosylated BSA
1.
2.
3.
SDS-PAGE analysis of native and glycated BSA: Aliquots of native and glycated BSA incubated for different times were subjected to 12 % SDS-PAGE. After
electrophoresis, the gel was stained with Coomassie
brilliant blue (CBB). Protein molecular weight markers were run to compare differences in molecular
weights of native and glycated BSA.
Fluorescence measurements: Fluorescence of the
advanced glycated end-products was monitored by
use of an F-4500 fluorophotometer (Hitachi, Japan).
The excitation wavelength, kex, was 320 nm and
emission was recorded in the range 335–500 nm
(Coussons et al. 1997). The desired final protein
concentration was 2 lM. Both excitation and emission
slit widths were 5 nm.
Nitroblue tetrazolium (NBT) assay: The extent of
glycation of BSA incubated with ribose was assessed
by NBT assay (Mendez et al. 2005). 200 ll
0.75 mM NBT was added to a 96-well microplate
with 10 ll sample or standard. The kinetics of NBT
reduction by fructosamine was studied by absorbance
changes at 540 nm, after incubation for 30 min at
37 °C, by use of an MK3 microplate reader (Thermo,
USA). Standard curves were generated by addition of
Eur Biophys J
10 ml 1-deoxy-1-morpholino-D-fructose
Sigma–Aldrich, USA).
(1-DMF;
Glycation-induced tertiary structure change in BSA
1.
2.
Intrinsic fluorescence analysis: Intrinsic fluorescence
of native and glycated BSA (2 lM) was monitored by
use of an F-4500 fluorescence spectrophotometer
(Hitachi, Japan). The emission spectrum from 300 to
400 nm was recorded after excitation at 280 and
295 nm at 25 °C.
Extrinsic (ANS) fluorescence measurement: A stock
solution of 1 mM ANS (Sigma, USA) was prepared in
20 mM Tris–HCl (pH 7.4). BSA (2 lM) and ANS
(100 lM, Sigma–Aldrich) were mixed at room temperature for 1 h, and the fluorescence was subsequently measured by recording the emission spectrum
from 400 to 600 nm (kex = 350 nm).
Glycation-induced secondary structure change in BSA
Circular dichroism measurement: Far-UV CD measurements were performed by use of a circular dichroism
chiroptical spectrometer (Applied Photophysics, Chirascan-Plus, UK). Samples in a 1 mm quartz cuvette were
maintained at 25 °C with a circulating water bath. Spectra
of ribosylated BSA (0.2 mg/ml) at different times were
measured in the range 190–250 nm with a step size of
1.0 nm. Each measurement was repeated thrice and
averaged.
Ribosylation-induced amyloid structure in BSA
either exposed or not exposed to the glycated protein
(0–40 lM) for 24 h. The culture medium was then
changed to DMEM containing 10 % fetal bovine serum.
MTT (final concentration 0.5 mg/ml; 50 ll) was added
after adding the glycated protein. Plates were incubated at
37 °C for 4 h, then the assay was stopped by replacement
of the MTT-containing medium with 150 ll dimethyl
sulfoxide (DMSO) and absorbance at 540 nm was recorded by use of a Multiscan MK3 (Thermo Electron Corporation, USA).
Reactive oxygen species (ROS) measurement: The level
of cytosolic ROS was measured by use of DCFH-DA
(Beyotime, China) as described by Smith et al. (2005).
Briefly, MCF-7 cells were grown in a 24-well plate and
incubated with ribose, BSA, and ribose-glycated BSA for
24 h. Normal cells were used as controls. Cells were
washed with PBS and incubated with DCFH-DA for
30 min. DCFH-DA was initially nonfluorescent and was
converted by oxidation to the fluorescent molecule DCFH
(kex 485 nm/kem 538 nm). DCFH was then quantified by
use of a CytoFluor multi-well plate reader (Fluoroskan
Ascent, Thermo Lab Systems, USA).
Results and discussion
Glycation of serum albumin has been widely studied in
recent years (Day et al. 1979; Luciano Viviani et al. 2008)
and bovine serum albumin (BSA) is commonly used as
molecular model. Epidemiological studies have established
that reduced levels of serum albumin are associated with an
increased mortality risk. Moreover, in the diseased population and in the general population, it has been estimated
that the odds of death increase by approximately 50 % for
Thioflavin T binding assay: Free ThT has excitation and
emission maxima at 350 and 450 nm, respectively. However, upon binding to fibrils the excitation and emission
maxima change to 450 and 485 nm, respectively (Naiki
et al. 1989). Native and glycated BSA samples (5 ll) were
added to solution containing 20 lM ThT in 20 mM TrisHCl buffer, pH 7.4, and shaken a few times before measurement of fluorescence at room temperature. A background fluorescence spectrum obtained by running blank
buffer was subtracted from each sample fluorescence
spectrum. The excitation wavelength was 444 nm, and
emission was recorded at 482 nm. Fluorescence intensity at
482 nm was plotted against time.
Cytotoxicity of ribosylated BSA to breast cancer cell
line MCF-7
Cell viability (MTT) assay: MCF-7 cells were seeded on a
96-well plate at a concentration of 105 cells per well and
Fig. 1 Changes in fluorescence during protein riboslyation. BSA
(0.75 mM) was incubated with 1 M D-ribose at 37 °C and aliquots
were taken at different times. Glycophore fluorescence was measured
at kex 320 and spectra were recorded between 320 and 500 nm. The
protein concentration used was 2 lM
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each 2.5 % g/l decrement in the initial albumin level.
Importantly, human serum albumin have extensive structural similarity (Brown 1976), so BSA instead of HSA was
used in this study because of its low cost and ready
availability.
According to Liu and Metzger (2007), glycation of a
protein produces a new fluorescence derivative (kex
320 nm, kem 410 nm), and thus fluorescence is commonly
used to monitor the formation of AGEs. As shown in
Fig. 1, fluorescence of ribose-glycated BSA increased
markedly with time. BSA alone, used as a negative control,
did not fluoresce at 410 nm.
The increase (%) in the relative intensity of the fluorescence for ribose-glycated BSA was rapid, with an
increase of 16 %/day during the incubation period. Interestingly, ribosylation of BSA starts very early from the first
day of incubation and maximum fluorescence is reached
after 14 days. However, fluorescence intensity decreases
from days 21 to 30; this might be because of protein precipitation and aggregation with more days of incubation
and/or reaction. Our results clearly demonstrate ribosylation is rapid, owing to the non-planar nature of ribose
which provides more flexibility to react with proteins and
other biomolecules, including DNA.
Fructosamine is a common product of glycation, and
the fructosamine content of a given protein reflects its
degree of glycation (Mosca et al. 1987; Baker et al.
1985). Assay of fructosamine with nitroblue tetrazolium
(NBT) is based on a color change correlated with
Fig. 2 Detection of AGE by NBT assay The conditions for glycation
of BSA were the same as for Fig. 1. Fructosamine was assayed with
nitroblue tetrazolium. The kinetics of reduction of NBT by the
fructosamine group (0.1 M carbonate buffer, pH 10.35) were measured at 540 nm after incubation for 30 min at 37 °C. Standard curves
were generated by addition of 10 ml 1-deoxy-1-morpholino-Dfructose
Fig. 3 SDS-PAGE analysis of native and glycated BSA. 12 % SDSPAGE was run for native and ribosylated BSA. Aliquots of
ribosylated BSA incubated for different times were taken and 20 lg
of protein was loaded into each lane. The first lane contains protein
molecular weight marker. The next lane contains native BSA alone,
used as control. The other lanes contain ribosylated BSA after
incubation for 1, 2, 3, 7, 14 and 21 days
123
Fig. 4 Conformational changes in glycated BSA observed by
measurement of intrinsic fluorescence. Experimental conditions were
the same as those used for Fig. 1. Fluorescence spectra of BSA
glycated with D-ribose after different reaction times: a excitation
wavelength 280 nm; b excitation wavelength 295 nm. The protein
concentration used was 2 lM and excitation and emission slits were
set at 5 nm
Eur Biophys J
reduction of NBT to monoformazan by Amadori rearrangement products in alkaline buffer. Here, we used
NBT to monitor the time course of formation of fructosamine during glycation. As shown in Fig. 2, absorbance at 540 nm increased markedly with time.
Absorbance increased rapidly on day 1 and then gradually
reached a plateau. The increase in absorbance demonstrates formation of advanced glycation end products after
reaction of ribose with BSA.
SDS-PAGE analysis of native and glycated BSA at
different times (Fig. 3) revealed structural change in BSA
and changes of apparent molecular weight after ribosylation. Retardation of protein bands was observed during
Fig. 5 a Changes in ANS fluorescence of BSA during glycation.
Experimental conditions were the same as those used for Fig. 1. ANS
(100 lM) was added to samples of ribosylated BSA for different
times. Fluorescence spectra of ANS were recorded at kex 350 nm. The
concentration of BSA used was 2 lM. b Changes in the fluorescence
of thioflavin T in the presence of ribosylated BSA after different
times. ThT (20 lM) was added to samples of BSA in different
concentrations of D-ribose for different times. The intensity of ThT
fluorescence was recorded (kex 444 nm; kem 482 nm). The concentration of BSA used was 2 lM
glycation of BSA in the presence of ribose. The increasing
molecular weight of BSA probably resulted from bound
ribose. Furthermore, protein degradation could also be seen
from 14th and 21st day of incubation.
To investigate whether ribosylation induced a change
in the tertiary structure of BSA, we took aliquots after
different incubation times and measured the intrinsic
fluorescence of the protein (total protein fluorescence at
kex 280 nm, kem 300–400 nm, and tryptophan fluorescence at kex 295 nm). As depicted in Fig. 4a, the intensity
of intrinsic fluorescence decreased when BSA was incubated with D-ribose for different times. Also, the environment of tryptophan residues was perturbed in the
presence of ribose. The decrease in fluorescence intensity
(Fig. 4b) reaffirms the change in the environment of
aromatic residues as a result of ribosylation. It is also
indicative of the increase in polarity caused by ribose
binding.
The fluorescent molecule 8-anilino-1-naphthalenesulfonate (ANS), which is frequently used to demonstrate the
presence of partially folded conformations of globular
proteins (Matulis and Lovrien 1998), was used to clarify
whether any hydrophobic patches become exposed at the
exterior of the BSA. Figure 5a shows that ribosylation
increased the ANS fluorescence intensity just after (i.e. on
the first day) incubation with ribose. Thereafter, the ANS
fluorescence intensity decreased with incubation time.
These results are indicative of biphasic change in the
conformation of BSA after ribosylation. Also, hydrophobic
patches are more exposed at the surface which further leads
to protein aggregation. For investigation of ribosylationinduced protein aggregation and amyloid formation, we
used the thioflavin T binding assay. Our results demonstrate that D-ribose reacted quickly with BSA to promote
Fig. 6 Far-UV circular dichroism analysis of ribosylated BSA was
performed on a Chirascan-Plus (Applied Photophysics, UK) circular
dichroism spectrometer. Samples in a 1 mm quartz cuvette were
maintained at 25 °C. Spectra (190–250 nm; step size 1.0 nm) of
native and ribosylated BSA (0.2 mg/ml) were measured at different
times. Each measurement was repeated three times and averaged
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Eur Biophys J
aggregation of glycated products into ThT-positive aggregates (Fig. 5b).
Far UV-CD was used to determine the secondary
structure content of proteins. On the basis of secondary
structure, several classes of proteins were used in this study
including a-class, b-class, a ? b class, and proteins with
pronounced random coil conformation. a-class and a ? b
class proteins furnish two negative peaks, one at 208 nm
and other at 222 nm, whereas b-class proteins furnish a
single negative peak between 215 and 222 nm. Random
Fig. 7 Effect of ribosylated
BSA on the viability of breast
cancer cell line MCF-7. Cell
viability of MCF-7 cells was
measured after adding
0.5–40 lM ribosylated BSA.
a Morphological change in
MCF-7 after seeding with
glycated-BSA. b Cell viability
of MCF-7 in the presence of
gly-BSA
123
coil proteins give a single negative peak at approximately
200 nm. The far UV-CD result (Fig. 6) reveals a pronounced conformational change (increase in alpha helicity)
of BSA after incubation with ribose for 7 days. A second
transition is observed after ribosylation for 14–30 days.
The effect of ribosylated BSA on the viability of MCF-7
cells was examined by use of the MTT assay. Reduction in
cell viability was measured in the presence of ribosylated
BSA after glycation for 1–21 days (Fig. 7). The number of
viable cells decreased significantly when the cells were
Eur Biophys J
Fig. 8 Measurement of reactive oxygen species in MCF-7 cells
treated with glycated BSA. a Morphological change in MCF-7 in the
absence and presence of Gly-BSA: a, BSA alone; b, Gly-BSA after
7 days; c, Gly-BSA after 14 days; d, Gly-BSA after 21 days.
b Fluorescence measurement of DCF in MCF-7 cell lines. S1, GlyBSA after 7 days; S2, Gly-BSA after 14 days; S3, Gly-BSA after
21 days
incubated with ribosylated BSA, whereas cell viability did
not significantly change in the presence of native BSA or Dribose (Fig. 7a, b). The reduction in cell viability induced
by ribosylated BSA was concentration-dependent. To
identify the cause of cytotoxicity, we measured ROS
content; the results were indicative of an increase in fluorescence of DCF (Fig. 8b) after incubation of cells with
ribosylated BSA. The increase in ROS is clearly apparent
from the morphology of MCF-7 cells, and the extent of the
change increases with incubation time with glycated-BSA
(Fig. 8a). The increase in ROS is maximum with glycatedBSA formed after 21 days. Many studies have shown that
glycation leads to the production of ROS, which are
harmful to cellular metabolism and cause cell damage
(Sakurai and Tsuchiya 1988; Yan et al. 1994; Heath et al.
1996). Much attention has been devoted to study of the
production of hydroxyl radicals via glycation, and inhibition of subsequent damage caused by them (Kikuchi et al.
2003; Chetyrkin et al. 2008).
Some diseases, for example Alzheimer’s disease,
transmissible spongiform encephalopathies, pancreatic islet
amyloidosis, and familial amyloidosis are caused primarily
by aggregation of amyloid-like fibrils in organs and in the
circulation (Jackson and Clarke 2000). Recently, it has
been documented that amyloid-like fibrils are cytotoxic to
neuronal cells, BHK-21 cells, SKOV-3, and cancer cells
(Gharibyan et al. 2007; Zamotin et al. 2006). Whether
fibrillar proteins can be used as anti-cancer drugs in cancer
therapy is unclear. This work reaffirms the previously
stated hypothesis of amyloid like aggregation in proteins
upon glycation and hints at the development of prospective
anti breast cancer drugs.
Acknowledgment The authors extend their appreciation to the
Deanship of Scientific Research at KSU for funding this work through
research group project number RGP-VPP-215.
References
Baker JR, Metcalf PA, Johnson RN, Newman D, Rietz P (1985) Use
of protein based standards in automated colorimetric determinations of fructosamine in serum. Clin Chem 31:1550–1554
Baynes JW, Watkins NG, Fisher CI et al (1989) The Amadori product
on protein: structure and reactions. Prog Clin Biol Res
304:43–67
Bengmark S (2007) Advanced glycation and lipoxidation end
products—amplifiers of inflammation: the role of food. JPEN J
Parenter Enteral Nutr 31:430–440
Bourdon E, Loreau N, Blache D (1999) Glucose and free radicals
impair the antioxidant properties of serum albumin. FASEB J
13:233–244
Brown JR (1976) Structural origins of mammalian albumin. Fed Proc
10:2141–2144
Brownlee M (1995) Advanced protein glycosylation in diabetes and
aging. Annu Rev Med 46:223–234
Cai Y, Liu J, Shi Y, Liang L, Mou S (2005) Determination of several
sugars in serum by high-performance anion-exchange chromatography with pulsed amperometric detection. J Chromatogr A
1085:98–103
Chanshuai H, Yang Lu, Wei Yan, Rongqiao He (2011) D-Ribose
induces protein glycation and AGE formation and impairs spatial
cognition. PLoS One 6(9):e24623
Chen L, Wei Y, Wang X, He R (2009) D-Ribosylated Tau forms
globular aggregates with high cytotoxicity. Cell Mol Life Sci
66(15):2559–2571
123
Eur Biophys J
Chetyrkin SV, Mathis ME, Ham AJ, Hachey DL, Hudson BG,
Voziyan PA (2008) Propagation of protein glycation damage
involves modification of tryptophan residues via reactive oxygen
species: inhibition by pyridoxamine. Free Radic Biol Med
44:1276–1285
Coussons PJ, Jacoby J, McKay A, Kelly SM, Price NC, Hunt JV
(1997) Glucose modification of human serum albumin: a
structural study. Free Radic Biol Med 22(7):1217–1227
Culbertson SM, Vassilenko EI, Morrison LD, Ingold KU (2003)
Paradoxical impact of antioxidants on post-Amadori glycoxidation: counterintuitive increase in the yields of pentosidine and
Nepsilon-carboxymethyllysine using a novel multifunctional
pyridoxamine derivative. J Biol Chem 278:38384–38394
Day JF, Thorpe SR, Baynes JW (1979) Nonenzymatically glucosylated albumin. In vitro preparation and isolation from normal
human serum. J Biol Chem 254(3):595–597
Gharibyan AL, Zamotin V, Yanamandra K, Moskaleva OS, Margulis
BA, Kostanyan IA, Morozova-Roche LA (2007) Lysozyme
amyloid oligomers and fibrils induce cellular death via different
apoptotic/necrotic pathways. J Mol Biol 365(5):1337–1349
Heath MM, Rixon KC, Harding JJ (1996) Glycation-induced
inactivation of malate dehydrogenase protection by aspirin and
a lens molecular chaperone, alphacrystallin. Biochim Biophys
Acta 1315:176–184
Huck JH, Verhoeven NM, Struys EA et al (2004) Ribose-5-phosphate
isomerase deficiency: new inborn error in the pentose phosphate
pathway associated with a slowly progressive leukoencephalopathy. Am J Hum Genet 74:745–751
Jackson GS, Clarke AR (2000) Mammalian prion proteins. Curr Opin
Struct Biol 10(1):69–74
Kikuchi S, Shinpo K, Takeuchi M, Yamagishi S, Makita Z, Sasaki N,
Tashiro K (2003) Glycation—a sweet tempter for neuronal
death. Brain Res Rev 41:306–323
Kumar MS, Reddy PY, Kumar PA et al (2004) Effect of dicarbonylinduced browning on a-crystallin chaperone-like activity: physiological significance and caveats of in vitro aggregation assays.
Biochem J 379:273–282
Li SY, Sigmon VK, Babcock SA, Ren J (2007) Advanced glycation
endproduct induces ROS accumulation, apoptosis, MAP kinase
activation and nuclear O-GlcNAcylation in human cardiac
myocytes. Life Sci 80:1051–1056
Liu X, Metzger LE (2007) Application of fluorescence spectroscopy
for monitoring changes in nonfat dry milk during storage.
J Dairy Sci 90:24–37
Love S, Barber R, Wilcock GK (1999) Increased poly (ADPribosyl)ation of nuclear proteins in Alzheimer’s disease. Brain
122:247–253
Luciano Viviani G, Puddu A, Sacchi G, Garuti A, Storace D, Durante
A, Monacelli F, Odetti P (2008) Glycated fetal calf serum affects
the viability of an insulin-secreting cell line in vitro. Metabolism
57(2):163–169
Luthra M, Balasubramanian D (1993) Nonenzymatic glycation alters
protein structure and stability. A study of two eye lens
crystallins. J Biol Chem 268:18119–18227
Lyons TJ, Silvestri G, Dunn JA et al (1991) Role of glycation in
modification of lens crystallins in diabetic and nondiabetic senile
cataracts. Diabetes 40:1010–1015
Matulis D, Lovrien R (1998) 1-Anilino-8-naphthalene sulfonate
anion-protein binding depends primarily on ion pair formation.
Biophys J 74:422–429
Mendez DL, Jensen RA, McElroy LA, Pena JM, Esquerra RM (2005)
The effect of non-enzymatic glycation on the unfolding of
human serum albumin. Arch Biochem Biophys 444(2):92–99
123
Monnier VM (1989) Structure elucidation of a senescence cross-link
from human extracellular matrix: implication of pentoses in the
aging process. J Biol Chem 264:21597–21602
Mosca A, Carenini A, Zoppi F, Carpinelli A, Banfi G et al (1987)
Plasma protein glycation as measured by fructosamine assay.
Clin Chem 33:1141–1146
Mrudula T, Suryanarayana P, Srinivas PNBS et al (2007) Effect of
curcumin on VEGF expression in diabetic retina. Biochem
Biophys Res Commun 361:528–532
Naiki H, Higuchi K, Hosokawa M, Takeda T (1989) Fluorometric
determination of amyloid fibrils in vitro using the fluorescent
dye, thioflavin T1. Anal Biochem 177:244–249
Necula M, Kuret J (2004) Pseudophosphorylation and glycation of tau
protein enhance but do not trigger fibrillization in vitro. J Biol
Chem 279:49694–49703
Peters TJ (1996) All about albumin—biochemistry, genetics, and
medical applications. Academic Press, San Diego
Sakurai T, Tsuchiya S (1988) Superoxide production from nonenzymatically glycated protein. FEBS Lett 236:406–410
Seuffer R (1977) A new method for the determination of sugars in
cerebrospinal fluid. J Clin Chem Clin Biochem 15:663–668
Shaklai N, Garlick RL, Bunn HF (1984) Nonenzymatic glycosylation
of human serum albumin alters its conformation and function.
J Biol Chem 259:3812–3817
Shuvaev VV, Laffont I, Serot JM et al (2001) Increased protein
glycation in cerebrospinal fluid of Alzheimer’s disease. Neurobiol Aging 22:397–402
Sing R, Barden A, Mori T et al (2001) Advanced glycation end
products: a review. Diabetologia 44:129–146
Smith WW, Norton DD, Gorospe M, Jiang H, Nemoto S et al (2005)
Phosphorylation of p66Shc and forkhead proteins mediates
Abeta toxicity. J Cell Biol 169:331–339
Syrovy I (1994) Glycation of albumin: reaction with glucose,
fructose, galactose, ribose or glyceraldehyde measured using
four methods. J Biochem Biophys Methods 28:115–121
Tan AL, Forbes JM, Cooper ME (2007) AGE, RAGE, and ROS in
diabetic nephropathy. Semin Nephrol 27:130–143
Van der Knaap MS, Wevers RA, Struys EA et al (1999) Leukoencephalopathy associated with a disturbance in the metabolism of
polyols. Ann Neurol 46:925–928
Vlassara H (1996) Advanced glycation end products and atherosclerosis. Ann Med 28:419–426
Woodside JV, Yarnell JW, McMaster D et al (1998) Effect of
B-group vitamins and antioxidant vitamins on hyperhomocysteinemia: a double-blind, randomized, factorial-design, controlled trial. Am J Clin Nutr 67:858–866
Yan SD, Chen X, Schmidt AM et al (1994) Glycated tau protein in
Alzheimer disease: a mechanism for induction of oxidant stress.
Proc Natl Acad Sci USA 91:7787–7791
Yan W, Chanshuai H, Jun Z, Chen Lan, Rongqiao He (2012) DRibose in glycation and protein aggregation. Biochim Biophys
Acta 1820:488–494
Zamotin V, Gharibyan A, Gibanova NV, Lavrikova MA, Dolgikh
DA, Kirpichnikov MP, Kostanyan IA, Morozova-Roche LA
(2006) Cytotoxicity of albebetin oligomers depends on crossbeta-sheet formation. FEBS Lett 580(10):2451–2457
Zhang M, Kho AL, Kho N et al (2006) Glycated proteins stimulate
reactive oxygen species production in cardiac myocytes:
involvement of Nox2 (gp91phox)-containing NADPH oxidase.
Circulation 113:1235–1243