Enzyme Regulation in C(4) Photosynthesis : PURIFICATION AND PROPERTIES OF THIOREDOXIN-LINKED NADP-MALATE DEHYDROGENASE FROM CORN LEAVES.
NADP-malate dehydrogenase, a light-modulated enzyme of C(4) photosynthesis, was purified to homogeneity from leaves of corn. The pure enzyme was activated by thioredoxin m that was reduced either photochemically (with ferredoxin and ferredoxin-thioredoxin reductase) or chemically (with dithiothreitol). Unactivated corn leaf NADP-malate dehydrogenase had a molecular weight of 50,000 to 60,000 and was chromophorefree. The enzyme appeared to have a high content of serine and glycine and to contain both S-S and SH groups. Consequently, NADP-malate dehydrogenase seems to be capable of undergoing reversible oxidation/reduction during its photoregulation.
Jacquot
J P
JP
Section of Cell Physiology, Department of Plant and Soil Biology, University of California, Berkeley, California 94720.
Buchanan
B B
BB