Download Polyamines

NEWLY DISCOVERED HORMONES
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Polyamines (Putrescine, Spermidine, Sperrmine, Cadaverine )
Brassinosteroids
Salicylic acid (cut flowers and leafy vegetables)
Jasmonates (inhibitors)
Systemin
Alpha Tocopherols (antioxidants)
Fusicoccin (from Fusariutn amygdali)
Triacontanol (growth promoter extracted from alfalfa)
Turgorins
Batasins (causes dormancy in bulbils. Extracted from yam.)
Polyamines
POLYAMINES
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Definition
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Those hormones or compounds which possess two or more
than two amino groups.
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These are the polyvalent cation compounds that contain
two or more amino groups.
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found ubiquitously in all organisms (plants and animals as
well as bacteria)
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Because of their positive charge they can bind to many
macromolecules including DNA, RNA and protein (Kusano
et al., 2008)
POLYAMINES
 The diamine putrescine, the triamine spermidine and the
tetramine spermine are ubiquitous in plant cells (Smith et
al, 1979; Bagni and Pistocchi, 1992).
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They occur as free cations and as conjugates with phenolic
acids and macromolecules (Galston and Sawnhey, 1990).
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Their levels increase greatly in response to environmental
stresses, most notably under conditions of potassium
deficiency, water deficits, salinity stress, anaerobiosis and
acid stress (Flores et al, 1989).
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Because polyamines are synthesized by amino acid
decarboxylation reactions which consume H+, polyamine
accumulation may function as part of a homeostatic
mechanism to keep intracellular pH at a constant value
(Flores et al, 1985).
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Polyamines may also play a role in the regulation of DNA
replication and cell division, and are implicated in the control
of senescence and morphogenesis (Evans and Malmberg,
1989; Galston and Sawnhey, 1990).
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It has been proposed that polyamines could be part of an
intrinsic signaling network and membrane stabilization
(Kusano et al., 2008).
Polyamines also serve as precursors of several classes of
alkaloids (Smith et al, 1979; Flores et al, 1989; Hashimoto
and Yamada, 1994) which may play important roles in plant
defense against herbivores.
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Plant-based foods containing polyamines have considerable
impact on human health (Lima et al., 2011). Organic foods
contain markedly more polyamines than crops grown using
conventional procedures
POLYAMINES
Types of polyamines
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Among the most abundant and physiologically
active polyamines are
Putrescine
 Spermidine
 Spermine
 Cadaverine
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COMMON AND UNCOMMON DIAMINES
AND POLYAMINES FOUND IN PLANTS
PUTRESCINE
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Putrescine (sometimes spelled putrescin or putrescene) is an
organic
chemical
compound
NH2(CH2)4NH2
(1,4diaminobutane or butanediamine) formed by and having the
smell of rotting flesh.
It is related to cadaverine; both are produced by the breakdown
of amino acids in living and dead organisms. Putrescine and
cadaverine were first described by the Berlin physician Ludwig
Brieger in 1885.
Putrescine is synthesized in small quantities by healthy living
cells by the action of ornithine decarboxylase. The polyamines,
of which putrescine is one of the simplest, appear to be growth
factors necessary for cell division.
Putrescine
Chemical name
1,4-Diaminobutane
Other names
Tetramethylenediamine
Butane-1,4-diamine
Chemical formula
C4H12N2
Molecular mass
88.15 g/mol
Density
0.877 g/cm³
Melting point
27 °C
Boiling point
158-160 °C
PUTRESCINE SYNTHESIS
ARGININE DECARBOXYLASE (ADC)
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Arginine decarboxylase (ADC) (a chloroplast
localized enzyme (Borrell et al, 1995) is
induced by a variety of stresses (most notably
potassium deficiency; Watson and Malmberg,
1996) and is thought to be the enzyme
primarily responsible for environmental stressinduced putrescine accumulation (Galston and
Sawnhey, 1990):
PHYSIOLOGICAL ROLES OF PUTRESCINE
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Loss of regeneration capacity of rice in long term culture is associated
with massive accumulation of putrescine due to an increase in arginine
decarboxylase activity. Difluoromethylarginine, an inhibitor or arginine
decarboxylase, restored regeneration capacity to long-term cultures
(Bajaj and Rajam, 1996). Spermidine treatment also caused a
reduction in putrescine content and arginine decarboxylase activity and
restoration of plant regeneration ability (Bajaj and Rajam, 1996). In
contrast, putrescine promotes and difluoromethylarginine inhibits
somatic embryogenesis in eggplant (Yadav and Rajam, 1998).
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The alternative, more direct pathway of synthesis of putresine via
ornithine decarboxylation catalyzed by cytosolic ornithine decarboxylase
(ODC) [EC 4.1.1.17] is proposed to be of little importance in stressinduced putrescine accumulation, but may be critical in regulation of
developmental processes (Galston and Sawhney, 1990; Walden et al,
1997). Increased putrescine biosynthesis catalyzed by ornithine
decarboxylase promotes somatic embryogenesis in carrots (Bastola and
Minocha, 1995).
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Levels of putrescine are higher in a drought tolerant wheat cultivar in
comparison to a drought susceptible wheat cultivar. These wheat
cultivars also differ for oxidant stress resistance as assayed by
resistance to paraquat (Ye et al, 1997). Constitutively elevated levels of
Arg decarboxylase and Orn decarboxylase are correlated with paraquat
resistance in Conzya bonariensis (Ye et al, 1997). Arg decarboxylase
and Orn decarboxylase are differentially regulated in Conzya
bonariensis, with only the former detectable in 2 week-old plants. Orn
decarboxylase becomes more abundant than Arg decarboxylase in 10
week-old plants (Ye et al, 1997). Exogenously supplied putrescine
prevents oxidative damage in paraquat-resistant C. bonariensis (Ye et
al, 1997). In part this may be due to inhibition of paraquat uptake by
putrescine (Hart et al, 1993). Ye et al (1997) suggest that putrescine
and other polyamines could function directly or indirectly as free radical
scavengers.
CADAVERINE
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Cadaverine is a foul-smelling molecule produced by protein
hydrolysis during putrefaction of animal tissue. Cadaverine
is a toxic diamine with the formula NH2(CH2)5NH2, which is
similar to putrescine. Cadaverine is also known by the
names 1,5-pentanediamine and pentamethylenediamine
Cadaverine is the decarboxylation product of the amino acid
lysine.
However, this diamine is not purely associated with
putrefaction. It is also produced in small quantities by living
beings. It is partially responsible for the distinctive smell of
urine and semen.
Cadaverine
Chemical name
1,5-diaminopentane
Other names
pentamethylenediamine
pentane-1,5-diamine
Chemical formula
C5H14N2
Molecular mass
102.18 g/mol
Density
0.870 g/cm³
Melting point
9 °C
Boiling point
178-180 °C
BIOSYNTHESIS OF PUTRESCINE &
CADAVERINE
The diamine cadaverine is derived from the amino acid lysine by decarboxylation. Its
synthesis is catalyzed by lysine decarboxylase [EC 4.1.1.18]. Cadaverine may play an
important role in root development (Gamarnik and Frydman, 1991).
SPERMINE
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Spermine is a polyamine involved in cellular metabolism found
in all eukaryotic cells. Formed from spermidine, it is found in a
wide variety of organisms and tissues and is an essential
growth factor in some bacteria. It is found as a polycation at
physiological pH. Spermine is associated with nucleic acids and
is thought to stabilize helical structure, particularly in viruses.
Crystals of spermine phosphate were first described in 1678, in
human semen, by Anton van Leeuwenhoek. The name spermin
[sic] was first used by the German chemists Ladenburg and
Abel in 1888, and the correct structure of spermine was not
finally established until 1926, simultaneously in England (by
Dudley, Rosenheim, and Starling) and Germany (by Wrede. et
al).
Spermine
Systematic name N,N'-bis(3-aminopropyl)butane-1,4diamine
Other names
gerontine, musculamine and neuridine
Chemical
formula
C10H26N4
Molecular mass
202.34 g/mol
Density
x.xxx g/cm
Melting point
29°C
Boiling point
xx.x °C
3
SPERMIDINE
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Spermidine is a polyamine involved in cellular
metabolism that can be used to stimulate the enzyme,
T7 RNA polymerase, a type of RNA polymerase.
Inhibits neuronal nitric oxide synthase (nNOS).
Binds and precipitates DNA.
May be used for purification of DNA binding proteins.
Stimulates T4 polynucleotide kinase (This enzyme
transfers gamma phosphate from ATP to DNA or RNA)
activity.
Spermidine
Systematic name N-(3-aminopropyl)butane-1,4-diamine
N-(3-aminopropyl)-1,4-diaminobutane
Chemical formula C7H19N3
Molecular mass
145.25 g/mol
Properties
Density
0.925 g/mL at 25 °C
Melting point
xx.x °C
Boiling point
xx.x °C
Refractive index
n20/D 1.479(lit.)
Foreign activity
DNase, RNase, and protease, none detected
Storage temp.
2-8°C
BIOSYNTHESIS OF SPERMIDINE & SPERMINE
Spermidine, and spermine are synthesized from L-arginine and L-ornithine. Synthesis of
spermidine and spermine requires an aminopropyl group derived from SAM, and there may
be competition between the ethylene and polyamine biosynthesis pathways when
concentrations of SAM are limited. The primary (terminal) amines of polyamines are
oxidized by diamine oxidases, the secondary amines by polyamine oxidases.
SPERMIDINE AND SPERMINE SYNTHESIS
The condensation of decarboxylated SAM and putrescine is catalyzed by spermidine
synthase (putrescine aminopropyltransferase) [EC 2.5.1.16]. Further condensation of
spermidine with decarboxylated SAM, catalyzed by spermine synthase [EC 2.5.1.22],
produces the tetramine, spermine (Flores et al, 1989).
METABOLISM OF POLYAMINES
METABOLISM OF POLYAMINES
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In addition to serving as a precursor of spermidine and
spermine, putrescine has three other metabolic fates;
conjugation with hydroxycinnamic acids, metabolism to
gamma-aminobutyrate (GABA), and utilization in alkaloid
biosynthesis.
(see also discussion of GABA metabolism under
Aminotransferase reactions)
GABA can be derived from putrescine (via gammaaminobutyraldehyde) through the reactions catalyzed by
diamine
oxidase
[EC
1.4.3.6]
and
gammaaminobutyraldehyde dehydrogenase (Flores et al, 1989). As
noted in the discussion of Quaternary ammonium and
tertiary sulfonium compounds, the latter enzyme may be
the same as BADH involved in glycinebetaine synthesis
(Trossat et al, 1997).
Putrescine serves as precursor of the nicotine and tropane
alkaloids (Smith et al, 1979; Flores et al, 1989; Hashimoto
and Yamada, 1994), which may play important roles in
plant defense against herbivores.
MODE OF ACTION OF POLYAMINES
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Bonding
In polyamine, amino group contains +ve charge on NH+3
Which helps to bind with –vely charged phosphate group of
DNA and RNA. As a result of this combination, they often
increase transcription of DNA and translation of RNA. They
enhance or stimulate protein synthesis.
Cell cycle regulation
 Polyamines cause phosphorylation of proteins, they are
involved in the regulation of cell cycle by controlling the
phosphorylation of proteins that take part in cell cycle.
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HYDROXYCINNAMIC ACID CONJUGATES OF POLYAMINES
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Hydroxycinnamic amide (HCA) conjugates of
polyamines accumulate markedly in the floral apex
during flower development, and are implicated in
the development of competence to flower; certain
mutants of tobacco which are deficient in HCAs are
unable to flower, and male sterile mutants of maize
lack HCA accumulation in anthers (Flores et al,
1989). A novel polyamine conjugate, N4hexanoylspermidine, has been identified in
senescing pea ovaries and petals (Perez-Amador et
al, 1996).
PHYSIOLOGICAL FUNCTIONS OF POLYAMINES
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Membrane Stabilization – Stabilize Membrane Structure and Function e.g.
Thylakoid
DNA Stabilization – Interaction with Nucleic acid Spm-DNA complexes stabilize
DNAs against thermal denaturation. Spd also has same effects.
Enzyme Activity – Stimulate enzyme activity e.g. Kinases in animals and and F 1,6
bisphosphate in plant
Cell Division – Enhance Cell Division but polyamines are not involved in Cell
Elongation
Buffering of Cellular pH – The reversible protonation of multiple amino groups of
PAs, serves as buffer in the cells
Role in Flowering – Floral axis synthesizes large quantities of conjugate PAs de
novo
Development of Ovary and Ovule – The development of the ovary and ovules and
ovules during maturation seems highly sensitive to PAs.
Embryogenesis – Increases embryogenesis
Senescence – At the time of senescence, there is low amount of PAs.
Abiotic Stress Tolerance – Play significant role in abiotic stresses tolerance like
chilling, drought and salinity.
Auxin Correlation -Since auxin application increases PAs in plants, it is proposed
that auxins act through PAs to promote growth
Tuber formation,
Root initiation
Fruit ripening