Kung H F, Henning U
Proc Natl Acad Sci U S A. 1972 Apr;69(4):925-9. doi: 10.1073/pnas.69.4.925.
Experiments are reported that demonstrate that in E. coli the pyridine nucleotide-independent D- and L-lactate dehydrogenases and the aerobic L-alpha-glycerophosphate dehydrogenase are membrane bound. These enzymes differed from succinate dehydrogenase in that they could be solubilized by treatment with nonionic detergent while succinate dehydrogenase could not. The binding of these enzymes to membrane was measured in mutants constitutive for the synthesis of various dehydrogenases: in cells in which the amount of dehydrogenases synthesized was greater than in others, the enzymes described above (except succinate dehydrogenase) were found in part in the soluble fraction of the cell extracts. Experiments of oxygen uptake indicate that when a fraction of the enzymes became soluble, this soluble fraction is no longer functional in respiration. These results indicate that it is possible to prevent membrane attachment of certain dehydrogenases by the excess production of other dehydrogenases; it may be that dehydrogenases compete for identical binding sites.
据报道，实验表明在大肠杆菌中，不依赖吡啶核苷酸的D-和L-乳酸脱氢酶以及需氧L-α-甘油磷酸脱氢酶是膜结合的。这些酶与琥珀酸脱氢酶不同，因为它们可以通过用非离子洗涤剂处理而溶解，而琥珀酸脱氢酶则不能。在组成型合成各种脱氢酶的突变体中测量了这些酶与膜的结合：在合成脱氢酶量比其他细胞多的细胞中，上述酶（琥珀酸脱氢酶除外）部分存在于细胞提取物的可溶部分中。摄氧实验表明，当一部分酶变得可溶时，该可溶部分在呼吸作用中不再起作用。这些结果表明，通过过量产生其他脱氢酶有可能阻止某些脱氢酶与膜的附着；可能是脱氢酶竞争相同的结合位点。
