AI Article Synopsis
- An NADP+-specific isocitrate dehydrogenase was isolated from Rhizobium meliloti, requiring either manganese (Mn++) or magnesium (Mg++) for activity.
- The enzyme showed varying Km values of 2.00 x 10(-5) M for DL-isocitrate and 1.51 x 10(-5) M for NADP+, indicating its substrate affinity.
- Its activity was competitively inhibited by ATP, ADP, AMP, alpha-ketoglutarate, oxalacetate, and glyoxylate, and fluorescence studies revealed the presence of tryptophan, suggesting a complex structure with a molecular weight of about 60,000.
Article Abstract
An NADP+-specific isocitrate dehydrogenase has been purified and characterized from Rhizobium meliloti. The enzyme showed Mn++ or Mg++ requirement. The apparent Km values were 2.00 x 10(-5) M and 1.51 x 10(-5) M for DL-isocitrate and NADP+, respectively. The enzyme was inhibited by ATP, to a lesser extent by ADP and AMP. alpha-Ketoglutarate also inhibited the enzyme activity. Oxalacetate and glyoxylate together inhibited the enzyme activity. The inhibition was competitive. Studies with thiol inhibitors suggested that the enzyme contained a sulfhydryl group at or near the active site. The enzyme has an approximate molecular weight of 60,000. Fluorescence studies suggested that the enzyme contained tryptophan.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/BF00410178 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!