Abstract: | Ribulose bisphosphate carboxylase (EC 4.1.1.39
EC]
) activity wasvery low in tomato leaf extracts unless prepared in the presenceof Mg2+, and polyclar AT. With young leaves, but not with fully-expanded leaves, the RuBP carboxylase activityextracted was increased by prolonged illumination of the leaves(2 h). The main effect of the light treatment was to increasethe specific activity of the enzyme but there was also a smallincrease in RuBP carboxylase protein. Tomato leaf RuBP carboxylasein extracts had specific activities in the range 0.206µmol CO2 min1 mg-1 total protein extracted,or 0.51.2 µmol CO2 min1 mg1 RuBPcarboxylase, and an apparent Km (CO2) at 20 ?C of 9.3 ? 1.2µM (using a of 6.407). Key words: Tomato leaf, RuBP carboxylase, Properties |