| Autor: |
Saha Englard, Lewis Siegel |
| Rok vydání: |
1961 |
| Předmět: |
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| Zdroj: |
Biochimica et Biophysica Acta. 54:67-76 |
| ISSN: |
0006-3002 |
| DOI: |
10.1016/0006-3002(61)90938-6 |
| Popis: |
Malic dehydrogenase has been purified from acetone-dried powders of thoroughly washed minces of whole beef heart. The enzyme appears to be homogeneous as determined by ultrcentrifugation studies and electrophoretic analysis over a wide pH range. The enzyme was found to have a sedimentation velocity constant of 4.3·10 −13 sec at 20° and a diffusion constant of 6.45·10 −7 cm 2 ·sec −1 , corresponding to a molecular weight of 62000 assuming a partial specific volume of 0.74 ml·g −1 Some kinetic constants have been determined and compared with the corresponding values obtained with other purified malic dehydrogenase preparations. The oxidation of DPNH is sensitive to elevated concentrations of oxaloacetate a finding which would characterize this enzyme kinetically as originating from the mitochondrial fraction. Malic dehydrogenase prepared directly from acetone-dried powders of light-layer beff-hart mitochondria yielded a preparation with molecular constants which agree well with those reported above for the enzyme obtained from whole beef-heart acetone powders. This finding further indicates that the enzyme under considerations is of mitochondrial origin. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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