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：1981
卷号：78
期号：12
页码：7737-7741
DOI：10.1073/pnas.78.12.7737
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We developed a radioimmunoassay to quantitate material crossreacting immunochemically with human methylmalonyl-CoA mutase (methylmalonyl-CoA CoA-carbonylmutase, EC 5.4.99.2 ), and have applied this assay to extracts of fibroblasts from controls and from 32 patients with methylmalonic acidemia due to inherited deficiencies in mutase activity. Four control lines had an average of 237 ng of crossreacting material (CRM) per mg of cell protein (range, 193-297 ng/mg). Mutant lines from each of the four cbl complementation groups of inherited methylmalonic acidemia, which have normal amounts of mutase activity in vitro, contained quantities of CRM comparable to those of control lines. On the other hand, 28 cell lines from the mut complementation group, which express mutations at the structural gene locus for the mutase apoenzyme, contained widely diverse amounts of CRM. Each of seven lines from the mut- subgroup, whose residual mutase activity reflects the presence of a structurally altered mutase protein with reduced affinity for cofactor, had detectable CRM ranging from 20% to 100% of control. The 21 lines from the mut0 group, which have no detectable mutase activity in vitro, fell into two populations with regard to CRM: 9 lines had detectable CRM ranging from 3% to 40% of control; 12 others had no detectable CRM (limit of detectability, less than 1% of control). These results emphasize the wide range of mutations at a single structural gene locus that can result in deficient enzyme activity.
