不同动物肝脏和肠道中酪胺与硫酸盐的结合作用。
The conjugation of tyramine with sulphate by liver and intestine of different animals.
作者信息
Wong K P
出版信息
Biochem J. 1976 Dec 15;160(3):491-3. doi: 10.1042/bj1600491.
Tyramine was conjugated with sulphate by extracts of monkey intestine and livers of monkey, rat, mouse, guinea pig and man. The activity measured in monkey intestine was almost three times that of monkey liver. Labelled tyramine sulphate synthesized from [14C] tyramine, [3H] tyramine or Na235SO4, on acid hydrolysis, released its radioactive precursor. Liver extracts of monkey, rat, mouse and guinea pig synthesized respectively 145,66,21 and 6 pmol of [14C] tyramine sulphate/min per mg of protein. Except with the monkey, intestine exhibited very low activity. trans-2-Phenylcyclopropylamine, a monoamine oxidase inhibitor, was added as a routine to the enzyme preparation, as its omission resulted in the production of p-hydroxyphenylacetic acid in appreciable amounts. This oxidative deamination of tyramine, however, did not decrease the sulpho-conjugation of tyramine. The low Km (9.1 muM) of sulphotransferase for tyramine is probably responsible.
酪胺可被猴肠道提取物以及猴、大鼠、小鼠、豚鼠和人的肝脏提取物硫酸化结合。在猴肠道中测得的活性几乎是猴肝脏的三倍。由[¹⁴C]酪胺、[³H]酪胺或Na₂³⁵SO₄合成的标记硫酸酪胺，在酸性水解时会释放出其放射性前体。猴、大鼠、小鼠和豚鼠的肝脏提取物每毫克蛋白质每分钟分别合成145、66、21和6皮摩尔的[¹⁴C]硫酸酪胺。除猴外，肠道的活性非常低。作为常规操作，向酶制剂中添加了单胺氧化酶抑制剂反式-2-苯基环丙胺，因为不添加它会导致大量对羟基苯乙酸的产生。然而，酪胺的这种氧化脱氨作用并没有降低酪胺的硫酸化结合。硫酸转移酶对酪胺的低Km值（9.1μM）可能是原因所在。
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