Matuszewska B, Borchardt R T
J Neurochem. 1983 Jul;41(1):113-8. doi: 10.1111/j.1471-4159.1983.tb11821.x.
Histamine N-methyltransferase (EC 2.1.1.8) was purified 4400-fold in 12% yield from guinea pig brain. The basic steps in the purification included differential centrifugation, calcium phosphate adsorption, DEAE-cellulose chromatography, and affinity chromatography on an S-adenosylhomocysteine-agarose matrix. The resulting protein was homogeneous by gel electrophoresis and was stable for at least 3 months at -80 degrees C. It had an apparent molecular weight of 29,000 +/- 1000 as determined by both gel filtration through Sephadex G-100 and by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. The isoelectric point of the protein was found to be 5.3. The pH optima for methylation of histamine were determined to be 7.5 and 9.0; the KmS for histamine and S-adenosyl-L-methionine were 13.57 +/- 0.74 microM and 6.1 +/- 0.12 microM, respectively; the Ki for S-adenosyl-L-homocysteine was 24.5 +/- 1.45 microM.
组胺N-甲基转移酶（EC 2.1.1.8）从豚鼠脑中纯化，纯化倍数达4400倍，产率为12%。纯化的基本步骤包括差速离心、磷酸钙吸附、DEAE-纤维素层析以及在S-腺苷同型半胱氨酸-琼脂糖基质上进行亲和层析。通过凝胶电泳检测，所得蛋白质呈均一性，在-80℃下至少可稳定保存3个月。通过Sephadex G-100凝胶过滤以及十二烷基硫酸钠-聚丙烯酰胺凝胶电泳测定，其表观分子量为29,000±1000。该蛋白质的等电点为5.3。确定组胺甲基化的最适pH值为7.5和9.0；组胺和S-腺苷-L-甲硫氨酸的Km值分别为13.57±0.74μM和6.1±0.12μM；S-腺苷-L-同型半胱氨酸的Ki值为24.5±1.45μM。
