Autor: |
Jordan, Douglas B, Basarab, Gregory S, Steffens, James J, Lundqvist, Tomas, Pfrogner, Beverly R, Schwartz, Rand S, Wawrzak, Zdzislaw |
Zdroj: |
Pesticide Science (now called Pest Management Science); March 1999, Vol. 55 Issue: 3 p277-280, 4p |
Abstrakt: |
The catalytic mechanism of scytalone dehydratase was examined by studying alternative substrates and site-directed mutations of active-site residues. Searches for an enol intermediate by looking for a half-reaction with authentic scytalone and 3,4-dihydro-6,8-dihydroxy-1-(2H)-2-[13C]naphthalenone were negative. An alternative substrate, 2,3-dihydro-2,5-dihydroxy-4H-benzopyran-4-one (DDBO), was nearly equal to scytalone as substrate for the enzyme, and DDBO's anomeric effect in stabilizing a partial carbocation center at C3 does not substantially contribute to the mechanism. Kinetic analysis of site-directed mutations of active-site amino acid side chains within the enzyme's active site provided an account for the role of these residues in the enzyme-catalyzed dehydration reactions. A concerted E2 elimination for the catalytic mechanism is proposed. © 1999 Society of Chemical Industry |
Databáze: |
Supplemental Index |
Externí odkaz: |
|