SPECIALIZED PRODUCTS FROM AMINO ACIDS [LIPPINCOTT S ] Deeba S. Jairajpuri

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1 SPECIALIZED PRODUCTS FROM AMINO ACIDS [LIPPINCOTT S ] Deeba S. Jairajpuri

2 CATECHOLAMINES Dpamine, nrepinephrine, and epinephrine are bilgically active amines that are cllectively termed catechlamines. Dpamine and nrepinephrine are synthesized in the brain and functin as neurtransmitters. Nrepinephrine is als synthesized in the adrenal medulla, as is epinephrine. Nrepinephrine and epinephrine are released frm strage vesicles in the adrenal medulla in respnse t fright, exercise, cld, and hypglycemia. They increase the degradatin f glycgen and triacylglycerl as well as increase bld pressure and cardiac utput. These effects are part f a crdinated respnse t prepare the individual fr stress fight-r-flight reactins.

3 SYNTHESIS OF CATECHOLAMINES The catechlamines are synthesized frm tyrsine. Tyrsine is first hydrxylated by tyrsine hydrxylase t frm 3,4-dihydrxyphenylalanine (DOPA) DOPA is decarbxylated in a reactin requiring pyridxal phsphate (PLP)t frm dpamine. Dpamine is hydrxylated by dpamine β-hydrxylase t yield nrepinephrine in a reactin that requires ascrbate (vitamin C) and cpper. Epinephrine is frmed frm nrepinephrine by a N-methylatin reactin.

4 PARKINSON DISEASE It is a neurdegenerative mvement disrder. Due t insufficient dpamine prductin as a result f the idipathic lss f dpamine-prducing cells in the brain. Administratin f L-DOPA (levdpa) is the mst cmmn treatment.

DEGRADATION OF CATECHOLAMINES The catechlamines are inactivated by xidative deaminatin catalyzed by mnamine xidase (MAO) and by methylatin carried ut by catechl-omethyl-transferase (COMT).

5 DEGRADATION OF CATECHOLAMINES The catechlamines are inactivated by xidative deaminatin catalyzed by mnamine xidase (MAO) and by methylatin carried ut by catechl-omethyl-transferase (COMT). The tw reactins can ccur in either rder. The metablic prducts f these reactins are excreted in the urine as vanillylmandelic acid (VMA) frm epinephrine and nrepinephrine, and hmvanillic acid (HVA) frm dpamine.

6 CREATINE Creatine phsphate, als called phsphcreatine, is the phsphrylated derivative f creatine fund in muscle. Creatine phsphate is a high-energy cmpund that prvides a small but rapid release f energy in the first few secnds f intense muscular cntractin. Creatine is synthesized in liver and kidney tissue frm glycine and arginine, plus a methyl grup frm SAM. Creatine is reversibly phsphrylated t creatine phsphate by creatine kinase, using ATP as the phsphate dnr. DEGRADATION: Creatine and creatine phsphate spntaneusly cyclize at a slw but cnstant rate t frm creatinine, which is excreted in the urine.

7 SEROTONIN It is als called as 5-hydrxytryptamine (5HT) which is synthesized and stred at several sites in the bdy. The largest amunt f sertnin is fund in intestinal cells Smaller amunts ccur in the CNS where it functins as a neurtransmittr. Sertnin is synthesized frm tryptphan The prduct, 5-hydrxytryptphan, is decarbxylated t sertnin Sertnin degradatin is als carried ut by mnamine xidase. Sertnin has multiple physilgic rles like pain perceptin, regulatin f sleep, appetite, temperature, bld pressure, cgnitive functins, and md (causes a feeling f well-being).

MELANIN AND HISTAMINE Melanin is a pigment that ccurs in several tissues, particularly in the eye, hair, and skin. It is synthesized frm tyrsine by pigment-frming cells called as melancytes.

8 MELANIN AND HISTAMINE Melanin is a pigment that ccurs in several tissues, particularly in the eye, hair, and skin. It is synthesized frm tyrsine by pigment-frming cells called as melancytes. It functins t prtect underlying cells frm the harmful effects f sunlight. A defect in melanin prductin results in albinism, the mst cmmn frm due t defect in cpper-cntaining tyrsinase Histamine is a chemical messenger that mediates a wide range f cellular respnses like allergic and inflammatry reactins. It is a pwerful vasdilatr Histamine is frmed by decarbxylatin f histidine. Histamine is secreted by mast cells as a result f allergic reactins r trauma.

CONVERSION OF AMINO ACIDS TO SPECIALIZED PRODUCTS DR. A. TARAB DEPT. OF BIOCHEMISTRY HKMU

CONVERSION OF AMINO ACIDS TO SPECIALIZED PRODUCTS DR. A. TARAB DEPT. OF BIOCHEMISTRY HKMU In addition to serving as building blocks for proteins, amino acids are precursors of many nitrogen-containing