Abstract
The synthesis of a new 8-spin-labeled analog of AMP, 8-[[[(2,2,5,5-tetramethyl-1-oxy-3-pyrrolidinyl)carbamoyl]methyl]thio]adenosine 5'-phosphate (8-slAMP), is described. The procedure is facile and results in high yields. 8-slAMP is a competitive inhibitor of AMP nucleosidase with a Ki of 19 microM as compared to a Km of 100 microM for AMP. The analog is not a substrate for the enzyme and does not displace MgATP2- from the allosteric sites under the usual assay conditions. The EPR spectrum of the bound spin probe reveals a highly immobilized nitroxide group. Binding studies with 8-slAMP at 8 degrees C indicate three independent binding sites (Kd = 1.4 microM) per molecule of enzyme (Mr = 320,000). These properties make 8-slAMP a good spin probe for AMP nucleosidase. The analog may also be useful for other proteins known or suspected of binding AMP analogs in a syn conformation.
Original language | English (US) |
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Pages (from-to) | 6215-6217 |
Number of pages | 3 |
Journal | Journal of Biological Chemistry |
Volume | 254 |
Issue number | 14 |
State | Published - Jul 25 1979 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology