Spencer D B, Hulett F M
J Bacteriol. 1981 Feb;145(2):934-45. doi: 10.1128/jb.145.2.934-945.1981.
Previous histochemical and biochemical localizations of alkaline phosphatase in Bacillus licheniformis MC14 have shown that the membrane-associated form of the enzyme is located on the inner surface of the cytoplasmic membrane, and soluble forms are located in the periplasmic space and in the growth medium. The distribution of salt-extractable alkaline phosphatase on the surfaces of the cytoplasmic membrane of B. licheniformis MC14 was determined by using lactoperoxidase-125I labeling techniques. Cells harvested during rapid alkaline phosphatase production were converted to protoplasts or lysed protoplasts and labeled. Analysis of the data obtained indicated that 30% of the salt-extractable, membrane-associated alkaline phosphatase was located on the outer surface of the cytoplasmic membrane, whereas 70% of the membrane-associated enzyme was localized on the inner surface. Controls for protoplast integrity (release of tritiated thymidine or examination of cytoplasmic proteins for label content) indicated excellent protoplast stability. Controls indicated that chemical labeling was not a factor in the apparent distribution of alkaline phosphatase on the membrane. These results support the previously reported histochemical localization of alkaline phosphatase on the membrane inner surface. The presence of alkaline phosphatase on the membrane outer surface is reasonable, considering the soluble forms of the enzyme found in the periplasmic region and in the culture medium.
先前对地衣芽孢杆菌MC14中碱性磷酸酶的组织化学和生化定位研究表明，该酶的膜结合形式位于细胞质膜的内表面，而可溶性形式位于周质空间和生长培养基中。利用乳过氧化物酶-125I标记技术测定了地衣芽孢杆菌MC14细胞质膜表面盐可提取碱性磷酸酶的分布。在碱性磷酸酶快速产生过程中收获的细胞被转化为原生质体或裂解原生质体并进行标记。对所得数据的分析表明，30%的盐可提取的、与膜相关的碱性磷酸酶位于细胞质膜的外表面，而70%的与膜相关的酶位于内表面。原生质体完整性的对照实验（氚标记胸腺嘧啶核苷的释放或检测细胞质蛋白的标记含量）表明原生质体稳定性良好。对照实验表明化学标记不是碱性磷酸酶在膜上明显分布的影响因素。这些结果支持了先前报道的碱性磷酸酶在膜内表面的组织化学定位。考虑到在周质区域和培养基中发现的酶的可溶性形式，碱性磷酸酶在膜外表面的存在是合理的。
