| | 1 | Author
| Heinz-W Alter, Scheid, Adelheid Ehmke, Thomas Hartm | Requires cookie* | | | Title
| Plant NAD-Dependent Glutamate Dehydrogenase. Purification, Molecular Properties and Metal Ion Activation of the Enzymes from Lemna minor and Pisum sativum  | | | | Abstract
| Glutamate dehydrogenase (L-glutamate: N A D + oxidoreductase (deaminating) EC 1.4.1.2) has been purified to homogeneity from Lemna minor and seeds o f Pisum sativum. As established by polyacrylamide gel electrophoresis the Pisum-enzyme constitutes a multiple pattern o f seven char ge isoenzymes whereas the Lemna enzyme shows one single protein band. Molecular weights of 230 000 were calculated for both enzymes by sedimentation equilibrium measurements (Pisum-enzyme]I and comparative gel filtration (Lemna-enzyme). Sodium dodecyl sulfate gel electropho resis and electron microscopic observations revealed that both enzymes are composed of four identical subunits (molecular weight 58 500) arranged in a tetraedric structure. The amino acid compositions of both enzymes are similar to those of various hexameric glutamate dehydrogen ases. The N-terminal amino acid of the Pisum-enzyme is alanine. Both enzymes require Ca2+ for maximal catalytic activity. For the Lemna-enzyme the K0.s values for Ca2+ are 22 /j.m (NADH-de-pendent reaction) and 4 piM (N A D +-dependent reaction), respectively. Ca2+ which to some extent can be replaced by Zn2+ does not affect the enzyme aggregation but seems to govern a reversible equilibrium between catalytically active and inactive enzyme forms. | | | |
Reference
| Z. Naturforsch. 35c, 213—221 (1980); received November 21 1979 | | | |
Published
| 1980 | | | |
Keywords
| Lemna minor, Pisum sativum, Glutamate Dehydrogenase, Purification, Molecular Properties, Me tal Ion Activation | | | |
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| default:Reihe_C/35/ZNC-1980-35c-0213.pdf | | | | Identifier
| ZNC-1980-35c-0213 | | | | Volume
| 35 | |
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