Abstract
Nuclei and mitochondria were isolated from hypocotyledonary hook sections of bush beans (Phaseolus vulgaris). Different methods of extraction were surveyed. The nuclei were purified by use of Triton x-100 and sucrose density gradient. Approximately less than 1% of the nuclear enzyme activity was due to mitochondrial contamination. In vitro, Triton was found to have no significant effect on the malate dehydrogenase (E.C. 1.1.1.37, MDH) activity of the nuclei or nuclear enzyme. However, the MDH activity of suspension of whole nuclei untreated with Triton was increased by Triton in vitro; this rise in activity was attributed to the lysis of contaminating mitochondria. Malate dehydrogenase and cytochrome c oxidase activity of the enzyme fractions from nuclei (n-MDH) and mitochondria (m-MDH) were assayed. Ratio of MDH: cytochrome c oxidase in nuclei and mitochondria, were significantly different (42.5 vs. 5.2). The rise in the activity of MDH following sonication of nuclei or mitochondria was 97 for n-MDK and about 5 for m-MDH. ...
Djavadi, Gholam Reza (1971). Regulatory and kinetic properties of malate dehydrogenase from plant nuclei. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -170361.