Subcellular distribution of multiple forms of glutathione reductase in leaves of pea (Pisum sativumL.)

摘要

On sodium-dodecyl-sulfate polyacrylamide gels, purified glutathione reductase (GR; EC 1.6.4.2) from the leaves of two- to three-week-old pea (Pisum sativumL. cv. Birte) seedlings was represented by a single band with an apparent molecular weight of 55 kilodaltons. This polypeptide was resolved to multiple isoforms by two-dimensional electrophoresis. Fractionation of protoplasts and purification of subcellular organelles has shown that enzyme activity is associated with the chloroplasts, mitochondria and cytosol (in this order, approx. 77, 3, and 20 of the total activity). Distinct multiple isoforms of the enzyme, which differed in isoelectric point and were compartment-specific, were resolved from purified mitochondria and chloroplasts. The latency of the glutathione reductase activity which co-purified on Percoll gradients with the mitochondrial marker enzyme, cytochrome-coxidase (EC 1.9.3.1.), indicated that this enzyme was within the mitochondrion. The mitochondrial glutathione reductase activity was strongly dependent on NADPH and not NADH.