Loading...
Please wait, while we are loading the content...
Similar Documents
Purification and characterization of a monomeric isocitrate dehydrogenase with dual coenzyme specificity from the photosynthetic bacterium Rhodomicrobium vannielii
| Content Provider | Scilit |
|---|---|
| Author | Leyland, Mark L. Kelly, David J. |
| Copyright Year | 1991 |
| Description | Journal: Journal of Biological Inorganic Chemistry An isocitrate dehydrogenase able to function with either NADP or NAD as coenzyme was purified to homogeneity from cell-free extracts of the purple photosynthetic eubacterium Rhodomicrobium vannielii using a rapid two-step procedure involving dye-ligand affinity chromatography. The enzyme was obtained in 60% yield with specific activities of 23 U.mg protein-1 (NADP-linked reaction) and 18.5 U.mg protein-1 (NAD-linked reaction). The purified enzyme was monomeric and migrated with an approximate Mr of 75,000-80,000 on both SDS/PAGE and non-denaturing PAGE. Affinity constants (Km values) of 2.5 microM for NADP and 0.77 mM for NAD and values for kcat/Km of 981,200 min-1.mM-1 (NADP) and 2455 min-1.mM-1 (NAD) indicated a greater specificity for NADP compared to NAD. A number of metabolites were examined for possible differential regulatory effects on the NADP- and NAD-linked reactions, using a dual-wavelength assay. Oxaloacetate was found to be an effective inhibitor of both reactions and the enzyme was also sensitive to concerted inhibition by glyoxylate and oxaloacetate. The amino-acid composition and the identity of 39 residues at the N-terminus were determined and compared to other isocitrate dehydrogenases. The results suggested a relationship between the Rm. vannielii enzyme and the monomeric isocitrate dehydrogenase isoenzyme II from Vibrio ABE-1. |
| Related Links | http://onlinelibrary.wiley.com/doi/10.1111/j.1432-1033.1991.tb16347.x/pdf |
| Ending Page | 93 |
| Page Count | 9 |
| Starting Page | 85 |
| ISSN | 09498257 |
| e-ISSN | 14321327 |
| DOI | 10.1111/j.1432-1033.1991.tb16347.x |
| Journal | Journal of Biological Inorganic Chemistry |
| Issue Number | 1 |
| Volume Number | 202 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 1991-11-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: Journal of Biological Inorganic Chemistry Biotechnology and Microbiology Analytical Chemistry |
| Content Type | Text |
| Resource Type | Article |
| Subject | Biochemistry Inorganic Chemistry |
