胃组胺甲基转移酶：使用高度纯化的酶制剂对侧链甲基化组胺类似物对映体的不同甲基化率。

Gastric histamine methyltransferase: different methylation rates for enantiomers of side-chain methylated histamine analogues using a highly purified enzyme preparation.

作者信息

Barth H, Schunack W, Crombach M, Lorenz W

出版信息

Agents Actions. 1984 Apr;14(3-4):346-50. doi: 10.1007/BF01973824.

DOI:10.1007/BF01973824

Abstract

The inhibitor/activator and substrate properties of enantiomers of two methylated histamines (MH) were investigated using a histamine methyltransferase preparation which was purified 1207-fold from pig fundic mucosa by ultracentrifugation, ion-exchange chromatography on DEAE-cellulose and preparative electrofocusing. In 1-100 microM concentrations, S-alpha-MH and R-alpha-MH were acceptor substrates as good as histamine itself. When substrate concentrations were increased to 1 mM these substances were methylated to an even greater extent than histamine, since they did not exert substrate inhibition on HMT. Introduction of a further methyl-group into the N alpha-position reduced acceptor substrate properties drastically. A difference in methylation was then seen since R-alpha,N alpha-DMH was a better substrate than S-alpha,N alpha-DMH. Whereas alpha-MH's could not activate HMT the alpha,N alpha-DMH's did. The poorer the substrate affinity of the investigated substances was, the better they were able to activate HMT.

摘要

使用一种组胺甲基转移酶制剂，研究了两种甲基化组胺（MH）对映体的抑制剂/激活剂和底物特性。该制剂通过超速离心、DEAE-纤维素离子交换色谱和制备性电聚焦从猪胃底黏膜中纯化了1207倍。在1-100微摩尔浓度下，S-α-MH和R-α-MH作为受体底物与组胺本身一样好。当底物浓度增加到1毫摩尔时，这些物质的甲基化程度比组胺更大，因为它们对HMT没有底物抑制作用。在Nα位引入另一个甲基会大大降低受体底物特性。然后观察到甲基化的差异，因为R-α，Nα-DMH是比S-α，Nα-DMH更好的底物。虽然α-MH不能激活HMT，但α，Nα-DMH可以。所研究物质的底物亲和力越差，它们激活HMT的能力就越强。