Kinetic Properties of Malic Dehydrogenase from Three Cultivars of Rice

摘要

Studies of enzymes such as malic dehydrogenase (MDH) and glutathione reductase(GR) from plant species suggest that thermal induced changes in kinetics may be indicators of the thermal regime to which the species are adapted. The investigation was undertaken to (1) gain knowledge of possible thermal induced changes in kinetics of MDH in cultivars of rice adapted to different climatic regimes, and (2) to assess the degree to which plant to plant variation contributes to variations seen in kinetic response. Among the results of the research were the following: (1) Plant extracts with significant MDH activity may be isolated from rice with conventional techniques developed for this enzyme in other species; (2) MDH activity shows some variation between plants within a cultivar; and (3) MDH from rice is responsive to temperature as indicated by the fact that apparent Km increased significantly with increasing temperature.