Effect of chemical modification in situ on L-glycerol-3-phosphate dehydrogenase in brown adipose tissue mitochondria.

Mitochondrial L-glycerol-3-phosphate dehydrogenase (E.C. 1.1.99.5.) was studied by chemical modification in situ with different amino acid side chain specific reagents in mitochondria isolated from hamster brown adipose tissue. The SH-modifying reagents have only slight effect on the enzyme activity. The most effective chemicals were tetranitromethane and diazobenzene sulfonic acid. The enzyme activity can be abolished completely by both of them. In the presence of Ca2+ and/or glycerol-3-phosphate inhibition was greater at the same electrophilic reagent concentration. The effect of Ca2+ and glycerol-3-phosphate is nonadditive on inhibition by these reagents.