Download Amino Acid

Lesson today
Protein
Teacher : Isroli
Laboratory : Animal Physiology and Biochemistry
Faculty : Animal Agriculture
Diponegoro University
Biological Functions of
Proteins
• Principal organic chemical constituents of body organs
and soft tissues
• Enormous functional diversity
–
–
–
–
–
–
–
–
Cell membrane structure and function
Enzymes
Hormones and other chemical messengers
Immune factors (antibodies)
Fluid balance
Acid-base balance
Transport
Source of energy and glucose
The Structure of Amino Acids
H
H 2N
CO 2H
C
R
NH2 amino group, COOH carboxyl group, R – side chain group can
be a series of functional groups
Amino Acids
• The monomer unit of proteins
R
O
C
C
H
NH2
HO
Chiral carbon
(L-series)
•R is the side chain.
•One of 20 different
chemical compounds
•Some R-groups are acid
(other alkali)
•Some R-groups are water
soluble (others are not)
Classification of Amino Acids
• Classification
– Structure
– Net charge
– Polarity
– Essentiality
• Neutral
– Aliphatic
– Aromatic
– Sulfur
• Acidic
• Basic
• Heterocyclic
Aliphatic (opened)
Aromatic
Sulfur
Acidic
Basic
Heterocyclic
Essentiality
• Essential
– Amino acids not synthesize in sufficient
amounts in the animal body
– Required in the diet
• Nonessential
– Adequately synthesized in the tissue
• No specific requirement
• Vary by species
Essential Amino Acids
•
•
•
•
•
•
Arginine
Histidine
Isoleucine
Leucine
Lysine
Methionine
•
•
•
•
•
•
Phenylalanine
Threonine
Tryptophan
Valine
Proline
Taurine
Abbreviations and Codes
Alanine A, Ala
Arginine R, Arg
Asparagine N, Asn
Aspartic acid D, Asp
Cysteine C, Cys
Glutamine Q, Gln
Glutamic Acid E, Glu
Glycine G, Gly
Histidine H, His
Isoleucine I, Ile
Leucine L, Leu
Lysine K, Lys
Methionine M, Met
Phenylalanine F, Phe
Proline P, Pro
Serine S, Ser
Threonine T, Thr
Tryptophan W, Trp
Tyrosine Y, Tyr
Valine V, Val
Northwest line Chung-San line
-C-C-C-N-C-N
=
Aromatic
N+
Arg
R
N
-C-
Lys
This is NOT a metabolic pathway
Trp W -C-OH
Tyr
K
-C-C-C-C-NH3+
Y
-C-C-CONH2
Asn
N
Gln
Q
Amide
Asp
D
Glu
E
Acidic
-C-
-C-C C
N N+
His
Phe
H
F
-C-COOH
Central line Gly G
Ala
-H
AA
Ser
S
Val
-C-C-COOH
V
C C
-C
-CH3
-C-OH
Cys
C -C-SH
Ile
Aliphatic
I
Polar
-C-C Thr
OH
T
Hydroxy
Met M -C-C-S-C
Sulfur
Leu
C
-C-C-C
Circular line
South line
Non-polar
Nan-Kan line
-C-CONH2
C
-C-C-C
C
C
C
HN C-COOH
a
Pro
P
L
Imino,
Circular
Juang RH (2004) BCbasics
Basic
Amino Acid Subway Map
Classification of Amino Acids by Polarity
NONPOLAR
POLAR
Acidic
Neutral
Basic
Asp
Asn Ser
Arg
Cys
Tyr
His
Gln
Thr
Lys
Glu
Gly
Ala Ile
Phe Trp
Val Leu Met Pro
Polar (hydrophilic) or non-polar (hydrophobic), it is the bases of the amino acid propert
Juang RH (2003) Biochemistry
The 20 Amino Acids Structure
TUGAS
Tulis structur 20 asam amino
berdasarkan klasifikasi berikut ini
1.
A.a. rantai samping alifatik
a) glisin
b) alanin
c) valin
2. A.a. rantai samping hidroksil
a) serin
b) treonin
3. A.a. rantai samping belerang
a) sistein
b) metionin
4. A.a. rantai samping karboksil
a) aspartic acid
b) asparagin
c) glutamic acid
d) glutamin
5. A.a. rantai samping basa
a) arginin
b) histidin
c) lisin
d) hidroksilisin
6. A.a. rantai samping cincin aromatik
a) tirosin
b) fenil alanin
c) tritofan
7. Asam imino
a) prolin
b) hidroksiprolin
Protein
Amino Acid (AA)-Protein
Amino acids: basic unit
Peptides: amino acid chain, containing 2 or more AA.
Polypeptides: containing less than 50 AA.
Protein: > 50 AA.
Peptides (from the Greek πεπτος, "digestible"), are formed through
condensation of amino acids through peptide bonds.
The Peptide Bond
• A peptide bond is an amide bond between the
carboxyl group of one amino acid and the amino
group of the next amino acid
O
||
+
H3N—CH2—C—O– +
CH3 O
|
||
+
H3N—CH—C—O–
O H CH3 O
|| |
|
||
+
H3N—CH2—C—N—CH—C—O– + H2O
peptide bond
Peptide Bonds
R
O
C
R
C
H
NH2
HO
O
C
C
H
NH2
Amino acids
R
O
HO
R
C
O
C
C
H
NH
HO
Water
C
H
NH 2
Peptide bond formation:
Disulfide Bonds
C SH
H2
HS C
H2
[O]
C S S C
H2
H2
• Two cysteine
molecules under
oxidizing conditions
• Intermolecular or
intramolecular crosslink
Protein Structures
Gly
Leu
Ser
Proteins consist of a long chain of
amino acids, the primary structure
Pro
Side chain
Amino acid
H R
H R
H
O
H
N
N
Backbone
H-bond
O
N
N
O
H
R H
O
H
R H
H
O
R H
H
O
R H
N
N
N
R
H
H
N
O
R
H
H
O