PURIFICATION AND CHARACTERIZATION OF CARNOSINE SYNTHETASE FROM MOUSE OLFACTORY BULBS
PURIFICATION AND CHARACTERIZATION OF CARNOSINE SYNTHETASE FROM MOUSE OLFACTORY BULBS
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DOI：
10.1111/j.1471-4159.1978.tb00127.x
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发表时间：
1978-01-01
影响因子：
4.7
通讯作者：
MARGOLIS, FL
中科院分区：
文献类型：
--
作者：
HORINISHI, H;GRILLO, M;MARGOLIS, FL
肌肽合成酶从小鼠嗅球纯化约500倍至约25 nmol/min/mg的比活性。这是一个增加了800倍以上，以前报道的这种酶从大鼠大脑和11倍以上的最高度纯化的酶从鸡胸肌。ATP是活性所必需的，不能被ADP取代。NAD对肌肽的合成无影响。关于β-测试了丙氨酸类似物，纯化的小鼠酶仅掺入GABA和β-氨基丁酸。氨基-正丁酸与组氨酸连接成肽。小鼠嗅球酶的肌肽合成被组氨酸类似物1-甲基组氨酸和3-甲基组氨酸竞争性抑制，Ki值至少是组氨酸Km值（16 μ M）的40倍。鸟氨酸和赖氨酸更有效。对于小鼠酶，丙氨酸受体比1-甲基组氨酸受体更强。酶从嗅上皮和腿骨骼肌的小鼠也表现出较高的Ki值为1-甲基组氨酸比Km值为组氨酸。来自鸡胸肌的肌肽-鹅肌肽合成酶给出组氨酸、1-甲基组氨酸和3-甲基组氨酸的Km值，其均在4-12 μ M的范围内。从小鼠和鸡的酶之间的底物特异性的差异意味着在这些物种的鹅丝氨酸合成的替代途径，并预测在小鼠大脑中的某些新的肽的发生。
Carnosine synthetase was purified about 500-fold from mouse olfactory bulb to a specific activity of approximately 25 nmol/min per mg. This is an increase of 800-fold over that previously reported for this enzyme from rat brain and 11 times higher than the most highly purified enzyme from chicken pectoral muscle. ATP was essential for activity and could not be replaced by ADP. NAD had no effect on the synthesis of carnosine. Of the .beta.-alanine analogues tested, the purified mouse enzyme incorporated only GABA and .beta.-amino-n-butyric acid into peptide linkage with histidine. Synthesis of carnosine by the mouse olfactory bulb enzyme was competitively inhibited by the histidine analogues, 1-methyl histidine and 3-methyl histidine, with Ki values which were at least 40 times the Km value for histidine (16 .mu.M). Ornithine and lysine were more efficient .beta.-alanine acceptors than 1-methyl histidine for the mouse enzyme. Enzyme from olfactory epithelium and leg skeletal muscle of mice also showed higher Ki values for 1-methyl histidine than the Km value for histidine. Carnosine-anserine synthetase from chicken pectoral muscle gave Km values for histidine, 1-methyl histidine and 3-methyl histidine, which were all in the range of 4-12 .mu.M. The differences in substrate specificity between the enzyme from mouse and chicken implies alternate routes of anserine synthesis in these species and predicts the occurrence of certain novel peptides in mouse brain.