Purification and properties of dehydroascorbate reductase from spinach leaves |
| |
Authors: | Christine H Foyer Barry Halliwell |
| |
Institution: | Department of Biochemistry King''s College London, Strand, London, WC2R 2LS, England |
| |
Abstract: | Dehydroascorbate reductase was detected in the leaves of several plants and has been partially purified from spinach leaves. The enzyme has a MW of ca 25 000, a pH optimum of 7.5, a Km for glutathione (GSH) of 4.43 ± 0.4 mM and a Km for dehydroascorbate of 0.34 ± 0.05 mM. High concentrations of dehydroascorbate inhibit the enzyme. Cysteine cannot replace GSH as a donor. The purified dehydroascorbate reductase is extremely unstable and also inhibited by compounds which react with thiol groups. Dehydroascorbate does not protect the enzyme against such inhibition. GSH reduces dehydroascorbate non-enzymically at alkaline pH values. |
| |
Keywords: | ascorbate dehydroascorbate glutathione chloroplasts dehydroascorbate reductase |
本文献已被 ScienceDirect 等数据库收录! |