期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1974
卷号：71
期号：10
页码：3805-3809
DOI：10.1073/pnas.71.10.3805
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Microsomal particles enriched up to 20-fold in glucose 6-phosphatase activity (as compared to crude microsomal fractions) were prepared from livers of phenobarbital-treated, normal, and diabetic rats by a method involving sucrose-density gradient centrifugation through a layer containing deoxycholate, followed by flotation of the delipidated particles in a phospholipid-detergent mixture. The flotation with phospholipid resulted in the extraction of additional protein, in a corresponding increase in specific activity, and in relipidation of the particles to their original phospholipid content. Detergents alone did not extract any additional protein. Relipidation caused a change in the properties of the microsomal membrane, as indicated by a 4-fold decrease in the Km for glucose 6-phosphate and mannose 6-phosphate. The maximal rate was not affected. The crude homogenate of diabetic rat liver contained more latent enzyme than that of normal rats. The diabetic rats also yielded purified microsomal particles of specific glucose 6-phosphatase activity twice that of normal and five times that of phenobarbital-treated rats, indicating that some regulatory mechanism exists for the incorporation of different amounts of the enzyme into the endoplasmic reticulum.
