Arnould J M
J Neurochem. 1987 Apr;48(4):1316-24. doi: 10.1111/j.1471-4159.1987.tb05663.x.
Carcinine biosynthesis was induced in vitro from its two components, beta-alanine and histamine. The reaction was catalyzed by muscle, heart, and CNS extracts from Carcinus maenas. The specific activity of the enzyme, carcinine synthetase, was 15 times higher in CNS than in other organs. Only CNS extracts induced biosynthesis of carcinine from histidine, and only in the presence of pyridoxal-5'-phosphate. Hence the seat of carcinine biosynthesis seems to be the CNS. It is highly probable that in the CNS, histidine is transformed into histamine, which is then catabolized into carcinine. The latter would then be transported and accumulated in the cardiac tissue. Thus histamine--the metabolism of which takes place totally within the CNS--would be implicated as a participant in the neuronal activity of Carcinus maenas. Carcinine synthetase is a soluble enzyme that requires the presence of ATP, beta-alanine, and histamine. Mg2+ and dithiothreitol are also essential for activity. Optimum pH is approximately 7.6. Carcinine synthetase differs from carnosine synthetase and gamma-glutamylhistamine synthetase in that it does not catalyze synthesis of beta-alanylhistidine or gamma-glutamylhistamine.
肌肽的生物合成可在体外由其两种成分β-丙氨酸和组胺诱导产生。该反应由食用黄道蟹的肌肉、心脏和中枢神经系统提取物催化。肌肽合成酶的比活性在中枢神经系统中比在其他器官中高15倍。只有中枢神经系统提取物能在有磷酸吡哆醛-5'-磷酸存在的情况下，从组氨酸诱导肌肽的生物合成。因此，肌肽生物合成的部位似乎是中枢神经系统。很有可能在中枢神经系统中，组氨酸转化为组胺，然后组胺被分解代谢为肌肽。然后，后者会被运输并积累在心脏组织中。因此，组胺——其代谢完全在中枢神经系统内进行——可能作为食用黄道蟹神经活动的参与者。肌肽合成酶是一种可溶性酶，需要ATP、β-丙氨酸和组胺的存在。镁离子和二硫苏糖醇对其活性也至关重要。最适pH约为7.6。肌肽合成酶与肌肽合成酶和γ-谷氨酰组胺合成酶的不同之处在于，它不催化β-丙氨酰组氨酸或γ-谷氨酰组胺的合成。
