华科同济医学院生物化学氨基酸代谢.pptxVIP

CHAPTER 7第 七 章氨 基 酸 代 谢Metabolism of Amino AcidsSection 5 Metabolism of Individual Amino Acids个别氨基酸的代谢一、Decarboxylation of amino acids generates special amines 氨基酸的脱羧基作用产生特殊的胺类化合物Decarboxylation (脱羧基作用)( 氨基酸脱羧酶)Amino acid decarboxylase+ CO2RCH2NH2PhosphopyridoxalAmines(磷酸吡哆醛)Amino acids胺类氨基酸Coenzyme pyridoxal phosphate磷酸吡哆醛 Monoamine oxidaseAminesCarboxlic acidsAldehyde羧酸类胺类醛类 COOH(CH2)2 CHNH2 COOHL- glutamate decarboxylase COOH(CH2)2 CH2NH2 CO2L-glutamateGABA（一） γ-aminobutyric acid, GABA (γ-氨基丁酸) is generated from glutamate catalyzed by glutamate decarboxylase 谷氨酸经谷氨酸脱羧酶催化生成γ-氨基丁酸(GABA)L- 谷氨酸脱羧酶γ-氨基丁酸L-谷氨酸GABA is a kind of inhibitive neurotransmitter which has inhibitive function to central nerve system.GABA是抑制性神经递质，对中枢神经有抑制作用。组氨酸脱羧酶CH2CHCOOHNH2CO2CH2CH2NH2HN NHN NL-histidineHistamine（二）Decarboxlation of histidine catalyzed by histidine decarboxlase generates histamine 组氨酸经组氨酸脱羧酶催化生成组胺Histidine decarboxlase组氨酸脱羧酶L-组氨酸组胺Histamine is an intensive vasodilator which can increase the permeability of blood capillary and stimulate the secretion of pepsinogen and gastric acid.组胺是强烈的血管舒张剂，可增加毛细血管的通透性，还可刺激胃蛋白酶原及胃酸的分泌。CH2CHCOOH NH2HOCH2CH2NH2（三）5-hydroxytryptamine, 5-HT (5-羟色胺 ) is generated from tryptophane via 5-hydroxytryptophan 色氨酸经5-羟色胺酸生成5-羟色胺 5-羟色氨酸脱羧酶5-hydroxytryptophan decarboxylaseCH2CHCOOH NH2HOCO2Tryptophan hydroxylaseTryptophane5-hydroxytryptophan色氨酸羟化酶5-HT色氨酸5-羟色氨酸5-羟色胺5-HT serving as neurotransmitter has inhibitive function in brain , and it also plays a role in contraction of blood vassele in peripheral tissues. 5-HT在脑内作为神经递质起抑制作用；在外周组织有收缩血管的作用。（四）Some amino acids can produce polyamines through decarboxylation 某些氨基酸的脱羧基作用可产生多胺类 OrnithineOnithine decarboxylase(鸟氨酸脱羧酶)Putrescine丙胺转移酶CO2Propylaminetransferase鸟氨酸腐胺SAM decarboxylase S-adenosyl methionine (SAM )DecarboxylatedSAM脱羧基SAMCO2SAM脱羧酶5-甲基-硫-腺苷S-腺苷甲硫氨酸5-methyl-S-adenosinePropylamine decarboxylase (丙胺转移酶)Spermidine (精脒 ) Spermine (精胺 )Polyamines are important substances responsible for regulati