College of Medicine
Al Imam Mohammad Ibn Saud Islamic University - Female Section Dr Gihan AlHusseini M Gawish
[email protected]
[email protected]
[email protected]
Conversion of Amino Acids to Specialized Products Creatine, Histamine, Serotonin, Catecholamine, Melanin
10th week, 2nd Semester
1
OBJECTIVE 2
1) To interpret the synthesis of creatine and creatinine 2) To interpret the role of creatine and creatinine in the body. 3) To interpret the synthesis and role of histamine in the body.
4) To interpret the synthesis and role of serotoninee in the body. 5) To interpret the synthesis and role of catecholamine and melanine in the body.
Lippincott’s Illustrated Reviews: Biochemistry
Dr Gihan Gawish
3
vitamin C
“fight-or-flight”
Dopamine and norepinephrine are synthesized in the brain as neurotransmitters. monoamine oxidase catechol-O-methyltransferase Norepinephrine is synthesized in the adrenal medulla response to fright, exercise, cold, and low levels of blood glucose as epinephrin Norepinephrine and its methylated derivative, epinephrine, are hormone regulators of carbohydrate and lipid metabolism
Synthesis of Catecholamines. PLP = pyridoxal phosphate Dr Gihan Gawish
Biosynthesis OF Catecholamines 4
Biosynthesis of Histamine 5
Histamine is a chemical messenger It
mediates
a
wide
range
of
cellular
responses, including: Allergic Inflammatory reactions Gastric acid secretion
Possibly neurotransmission in parts of the brain.
It is secreted by mast cells as a result of allergic reactions or trauma. Histamine has no clinical applications Agents interfere with the action of histamine have important therapeutic applications. Dr Gihan Gawish
Biosynthesis of Serotonin:(5-hydroxytryptamine)(5HT) 6
It is synthesized and stored at several sites in the body Largest amount found in intestinal mucosa. Smaller amounts occur in the central nervous system, It is synthesized from tryptophan, which is hydroxylated in a BH4 It is degraded by MAO. Serotonin is converted to melatonin in the pineal gland via acetylation and methylation. Functions: neurotransmitter, and in platelets. Multiple physiologic roles: Pain perception Regulation of sleep, Appetite Temperature Blood pressure Cognitive functions, and mood
Biosynthesis of Serotonin:(5-hydroxytryptamine)(5HT) 7
Dr Gihan Gawish
Biosynthesis of Creatine 8
Phosphocreatine:phosphor ylated derivative of creatine found in muscle High-energy compound Provides a small but rapidly mobilized reserve of highenergy phosphates transferred to ADP Maintain the intracellular level of ATP during the first few minutes of intense muscular contraction.
Creatin
Dr Gihan Gawish
The amount of creatine phosphate in the body is proportional to the muscle mass.
Biosynthesis and Degradation of Creatine 9
The presence of creatine kinase (MB isozyme) in the plasma is indicative of heart damage, and is used in the diagnosis of myocardial
infarction. Creatine and creatine phosphate cyclize to form creatinine, which is excreted in the urine.
The amount of creatinine excreted can be used to estimate muscle mass.
Blood creatinine is a sensitive indicator of kidney malfunction, A typical adult male excretes about 15 mmol of creatinine per day
Dr Gihan Gawish
Biosynthesis of Melanin 10
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. Its function is to protect underlying cells from the harmful effects of
sunlight. A defect in melanin production results in albinism, the most common form being due to defects in copper-containing tyrosinase
Dr Gihan Gawish
11
Dr Gihan Gawish
12
Dr Gihan Gawish
