Uncommon amino acids play important roles in proteins and biological processes. Some examples include: 1. 4-Hydroxyproline helps provide stability to collagen proteins. Hydroxyproline and proline allow collagen to form its tight helical structure. 2. Acetyllysine is involved in epigenetic regulation by controlling DNA binding through histone acetylation. 3. Sarcosine is an intermediate in glycine synthesis and degradation, and also contributes to taste and acts as a surfactant. 4. Many uncommon amino acids are involved in key metabolic pathways like the urea cycle or in important biochemical processes such as neurotransmitter synthesis and function.

1. UNCOMMON AMINO-ACID
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. INTRODUCTION
Amino acids are molecules containing an amine group, a carboxylic acid group and a
side-chain that varies between different amino acids. The key elements of an amino acid
are carbon, hydrogen, oxygen, and nitrogen. They are particularly important in
biochemistry, where the term usually refers to alpha-amino acids.

3. UNCOMMON AMINO-ACID
• Non standard amino acid residue are often
important constituent of protein and biologically
active polypeptide. Many amino acid, however, are
not the constituent of protein. Together they play a
verity of biologically important role.
UNCOMMON AMINO-ACID CAN BE CLASSIFIED
INTO TWO GROUP:-
AMINO-ACID DERIVETIVES IN PROTINE
SPECIALIZED ROLES OF AMINO-ACID

4. 4-HYDROXYPROLINE
• 4-Hydroxyproline, or
L-hydroxyproline
(C5H9O3N), is a
common non-
proteinogenic amino
acid.
• Hydroxyproline differs
from proline by the
presence of a hydroxyl
(OH) group attached
to the gamma carbon
atom.

5. PRODUCTION
Proline + α-ketoglutarate + O2 → 4-
hydroxyproline + CO2 + succinate

6. FUNCTION
• Hydroxyproline is a major
component of the protein
collagen. Hydroxyproline and
proline play key roles for collagen
stability.
• They permit the sharp twisting of
the collagen helix.

7. N-€-ACETYL-L-LYSINE:-
• Acetyllysine (or acetylated lysine) is an acetyl-
derivative of the amino acid lysine
Preferred IUPAC name
6-Acetamido-2-aminohexanoic acid

8. PRODUTION
• acetyltransferases (HATs) catalyze the addition
of acetyl groups from acetyl-CoA onto certain
lysine residues of histones and non-histone
proteins
• Histone acetyltransferases (HAT) are enzymes
that acetylate conserved lysine amino acids on
histone proteins by transferring an acetyl
group from acetyl CoA to form ε-N-acetyl
lysine.

9. FUNCTION
• In proteins, the acetylation of lysine
residues is an important mechanism
of epigenetics.
• It functions by regulating the binding
of histones to DNA in nucleosomes
and thereby controlling the
expression of genes on that DNA.

10. SCRCOSINE
• Sarcosine, also known as N-methylglycine, is
an intermediate and byproduct in glycine
synthesis and degradation
IUPAC name
2-(Methylamino)acetic acid

11. PRODUTION
• Sarcosine is metabolized to glycine
by the enzyme sarcosine
dehydrogenase, while glycine-N-
methyl transferase generates
sarcosine from glycine.
• Sarcosine is a natural amino acid
found in muscles and other body
tissues.

12. FUNCTION
• Sarcosine is sweet to the taste and dissolves in
water. It is used in manufacturing biodegradable
surfactants and toothpastes.
• Sarcosine is formed from dietary intake of choline
and from the metabolism of methionine, and is
rapidly degraded to glycine, which, in addition to
its importance as a constituent of protein, plays a
significant role in various physiological processes
as a prime metabolic source of components of
living cells such as glutathione, creatine, purines
and serine.

13. N-FORMYLMETHIONINE
• N-Formylmethionine (fMet) is a proteinogenic
amino acid found in Bacteria and related
Prokaryotic organelles.

14. PRODUCTION
• It is a derivative of the amino
acid methionine in which a
formyl group has been added
to the amino group.

15. FUNCTION
• fMet plays a crucial part in the protein synthesis
of bacteria, mitochondria and chloroplasts.
• fMet is a starting residue in the synthesis of
proteins in bacteria, and, consequently, is located
at the N-terminus of the growing polypeptide.
• fMet is delivered to the ribosome (30S) - mRNA
complex by a specialized tRNA (tRNAfMet) which
has a 3'-UAC-5' anticodon that is capable of
binding with the 5'-AUG-3' start codon located on
the mRNA.

16. AZASERINE
• Azaserine is a carcinogen primarily used for
researching pancreatic cancer in animal
models
Systematic (IUPAC) name
O-(2-Diazoacetyl)-L-serine

17. PRODUTION
• Amidophosphoribosyltransferase
(ATase), also known as glutamine
phosphoribosylpyrophosphate
amidotransferase (GPAT), is an
enzyme that in humans is encoded
by the PPAT (phosphoribosyl
pyrophosphate amidotransferase)
gene.

18. FUNCTION
• IMP is an important precursor to the purine
nucleotides which include Adenosine
monophosphate (AMP) and Guanosine
monophosphate (GMP).
• ATase is an enzyme that converts α-
phosphoribosylpyrophosphate (α-PRPP) into
5-β-phosphoribosylamine. The enzyme uses
the ammonia group from the glutamine side-
chain.

19. ORNITHINE
• Ornithine is an amino acid that plays a role in
the urea cycle.
IUPAC name
L-Ornithine

20. PRODUCTION
• L-Ornithine is one of the
products of the action of the
enzyme arginase on L-arginine,
creating urea.

21. FUNCTION
• Role in urea cycle
• ornithine is a central part of the urea cycle, which
allows for the disposal of excess nitrogen.
• First, ammonia is converted into carbamoyl
phosphate (phosphate-CONH2), which creates
one half of urea. Ornithine is converted into a
urea derivative at the δ (terminal) nitrogen by
carbamoyl phosphate.
• The nitrogens of urea come from the ammonia
and aspartate, and the nitrogen in ornithine
remains intact.

22. HISTAMINE
• Histamine is an organic nitrogen compound
involved in local immune responses as well as
regulating physiological function in the gut
and acting as a neurotransmitter.
IUPAC name
2-(1H-imidazol-4-yl)ethanamine

23. PRODUCTION
• Histamine is derived from the decarboxylation
of the amino acid histidine, a reaction
catalyzed by the enzyme L-histidine
decarboxylase. It is a hydrophilic vasoactive
amine.

24. FUNCTION
Type
Location
Function
H1 histamine receptor Found on smooth muscle,
endothelium, and central
nervous system tissue
Causes, bronchoconstriction, bronchial
smooth muscle contraction, separation of
endothelial cells (responsible for hives), and
pain and itching due to insect stings; the
primary receptors involved in allergic
rhinitis symptoms and motion sickness;
sleep regulation.
H2 histamine receptor Located on parietal cells
and vascular smooth
muscle cells
Primarily involved in
vasodilation. Also stimulate
gastric acid secretion
H3 histamine receptor
Found on central nervous
system and to a lesser extent
peripheral nervous system
tissue
Decreased neurotransmitter
release: histamine,
acetylcholine,
norepinephrine, serotonin

25. gamma-Aminobutyric acid
• Gamma- aminobutyric acid is the chief
inhibitory neurotransmitter in the
mammalian central nervous system . It plays a
role in regulating neuronal excitability throughout
the nervous system. In humans, GABA is also
directly responsible for the regulation of muscle
tone.

26. PRODUCTION
• GABA does not penetrate the blood-brain barrier;
it is synthesized in the brain. It is synthesized
from glutamate using the enzyme L-glutamic acid
decarboxylase and pyridoxal phosphate (which is
the active form of vitamin B6) as a cofactor via a
metabolic pathway called the GABA shunt.
• This process converts glutamate, the
principal excitatory neurotransmitter, into the
principal inhibitory neurotransmitter (GABA).

27. FUNCTION
• Neurotransmitter
• In vertebrates, GABA acts at inhibitory synapses in
the brain by binding to specific transmembrane receptors in
the plasma membrane of both pre- and postsynaptic neuronal
processes.
• This binding causes the opening of ion channels to allow the
flow of either negatively charged chloride ions into the cell or
positively charged potassium ions out of the cell.
• Brain development
• For the past two decades, the theory of excitatory action of
GABA early in development was unquestioned based on
experiments in vitro, on brain slices. The main observation
was that in the hippocampus andneocortex of the mammalian
brain, GABA has primarily excitatory effects, and is in fact the
major excitatory neurotransmitter in many regions of the
brain before the maturation of glutamateergic synapses.

28. CONCLUSION