This document summarizes several specialized products derived from amino acids and proteins, including histamine, melanin, creatine, and catecholamines. Histamine is a chemical messenger produced from histidine that causes vasodilation and bronchoconstriction. Melanin is a pigment synthesized from tyrosine that protects cells from sunlight. Creatine is produced from glycine, arginine, and S-adenosylmethionine and stored in muscle and brain to provide energy. Catecholamines like dopamine and norepinephrine are synthesized from tyrosine and function as neurotransmitters.

1. Specialized products of Amino
Acid and Protein
Dr Pashmina khan

2. Specialized products of Amino Acid and
Protein
 as building blocks for proteins, amino acids are
precursors of many nitrogen-containing
compounds that have important physiologic
functions These molecules include
 Creatine
 Neurotransmitters
 Melanin
 Histamine

3. Histamine
 Histamine is a chemical messenger
 Histamine is produced by decarboxylation of histidine
 a. Histamine causes vasodilation and bronchoconstriction.
 b. In the stomach, it stimulates the secretion of hydrochloric
acid (HCl).

4. Histamine

5.  Melanin is a pigment that occurs in several tissues,
particularly the eye, hair, and skin. It is synthesized
from tyrosine in the epidermis by pigment-forming
cells called melanocytes.
 the enzyme tyrosinase (which converts tyrosine to
melanin)
 Its function is to protect underlying cells from the
harmful effects of sunlight

6. melanin
 Albinism results from a
defect in the conversion
of tyrosine to melanin,
with partial or full
absence of this pigment
in the hair, skin, or eye.

7. Creatine
 Creatine is produced from
glycine, arginine, and S-
adenosylmethionine
(SAM). Glycine combines
with arginine to form
ornithine and
guanidinoacetate, which is
methylated by SAM to
form creatine.

8. Creatine
 Creatine travels from the liver to other tissues, where it is converted to
creatine phosphate.
 Adenosine triphosphate (ATP) phosphorylates creatine to form creatine
phosphate in a reactioncatalyzed by creatine kinase (CK).
 Muscle and brain contain large amounts of creatine phosphate.
 Creatine phosphate spontaneously cyclizes, forming creatinine, which is
excreted by the kidney

9. catecholamines
 catecholamines (dopamine, norepinephrine, and
epinephrine) biologically active amines
 Synthesis of catecholamines: The catecholamines are
synthesized from tyrosine
 Dopamine and norepinephrine are synthesized in the brain
 Norepinephrine is also synthesized in the adrenal medulla,
 function as neurotransmitters.
 Parkinson disease, dopamine levels decreased