Inactivation of B/sub 12/-dependent ribonucleotide reductase by 2'-azido-2'-deoxyarabinofuranosyladenine 5'-triphosphate
The Coenzyme B/sub 12/-dependent ribonucleotide triphosphate reductase (RTPR) from Lactobacillus leichmannii is rapidly inactivated by the substrate analog 2-azido-2'-deoxy-arabinofuranosyladenine 5'-triphosphate (N/sub 3/araATP). This reaction has been probed using N/sub 2/ araATP specifically radiolabeled in the sugar and base moieties. Unlike the inactivation of this enzyme by 2'-halo nucleotides, reaction of RTPR with N/sub 3/araATP does not result in formation of PPPi, adenine, or azide ion. Instead, the phosphate, sugar, and base moieties remain bound to the protein after gel filtration of the inactive protein. One equivalent of coenzyme is destroyed during the inactivation, producing 5'-deoxyadenosine and cob(II)alamin. No/sup 3/H/sub 2/O is formed when RTPR is inactivated with (3'-/sup 3/H)N/sub 3/araATP. These results suggest that inactivation occurs either through reaction of an enzyme group with the azido moiety or through formation of a tight-binding product.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 6936919
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATP
BIOCHEMICAL REACTION KINETICS
OXIDOREDUCTASES
ENZYME ACTIVITY
ADENINES
COENZYMES
INACTIVATION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINES
ANTIMETABOLITES
AROMATICS
AZAARENES
DRUGS
ENZYMES
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PURINES
REACTION KINETICS
550201* - Biochemistry- Tracer Techniques