title: Subcellular distribution of multiple forms of glutathione reductase in leaves of pea (Pisum sativum L.).
abstract: 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 sativum L. 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-c oxidase (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.
authors.affiliation: John Innes Institute and AFRC Institute of Plant Science Research, Colney Lane, NR4 7UH, Norwich, UK.
authors.forename: E A
authors.initials: EA
authors.lastname: Edwards
authors.forename: S
authors.initials: S
authors.lastname: Rawsthorne
authors.forename: P M
authors.initials: PM
authors.lastname: Mullineaux