Peter Owen1, John H. Freer1
1Department of Microbiology, University of Glasgow, Garscube Estate, Glasgow, U.K.
Tóm tắt
1. Some properties of succinate dehydrogenase [succinate–(acceptor) oxidoreductase, EC 1.3.99.1] in membrane preparations from Micrococcus lysodeikticus (N.C.T.C. 2665) were investigated. 2. In the spectrophotometric assay system adopted the reaction velocity was shown to be proportional to the amount of membrane added. Dichlorophenol-indophenol, reduced photochemically in the presence of phenazine methosulphate, or enzymically by the membrane-bound enzyme, was shown to undergo reoxidation in the dark. 3. The membrane-bound enzyme was found to be inactivated at temperatures above 10°C. 4. The specific activity of membrane-bound succinate dehydrogenase was found to increase between two- and three-fold in diluted membrane preparations equilibrated at 0°C for 6h. Membranes treated with sodium deoxycholate showed no enzyme activation on dilution but displayed maximal activity, all activity being sedimentable at 103000g. The increase in specific activity observed on dilution could be partially inhibited by fixation with glutaraldehyde, or by the presence of bovine serum albumin. 5. The addition of Mg2+ or Ca2+ ions to membrane suspensions caused an overall depression of enzyme activity. 6. The results suggest the presence of an `inhibitor' that affects the expression of membrane bound succinate dehydrogenase activity.
