Factor VIIa: Difference between revisions
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Upon attack on an amide bond, the lone electron pairs of the oxyanion and the nitrogen of the leaving group have to be antiperiplanar to the new bond. Therefore the lone pair of the amine leaving group points away from His193-H+. For the chemistry to occur the nitrogen must undergo inversion to position the lone pair for protonation by His193-H+<ref>PMID:2514538</ref>. | Upon attack on an amide bond, the lone electron pairs of the oxyanion and the nitrogen of the leaving group have to be antiperiplanar to the new bond. Therefore the lone pair of the amine leaving group points away from His193-H+. For the chemistry to occur the nitrogen must undergo inversion to position the lone pair for protonation by His193-H+<ref>PMID:2514538</ref>. | ||
[[Image:stereochemistry of N.jpg|center]] | [[Image:stereochemistry of N.jpg|center]] | ||
===Kinetics of action=== | |||
In general serine proteases have a three-step kinetic mechanim: 1) formation of an enzyme-substrate (E-S) complex, 2) acylation of the active site serine, and 3) hydrolysis of the acylenzyme intermediate. A large solvent isotope effect (~3) | |||
[[Image:kinetics.jpg|center]] | |||
==References== | ==References== | ||
<references /> | <references /> | ||