Analysis of Structure and Specific Functional Groups Involved in Acetylcholinesterase Catalysis and Inhibition.
Final rept. 14 Jun 91-13 Sep 94,
CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF PHARMACOLOGY
Pagination or Media Count:
The interactions of substrates, inhibitors and antibodies with Torpedo and mammalian acetylcholinesterases and butyrylcholinesterases have been studied by enzyme kinetic analyses, site-specific mutagenesis, molecular modeling, and peptide and antibody titrations. The high yield expression systems we developed have enabled us to obtain sufficient wild-type and mutant enzymes for the kinetic and physical studies. These studies have benefited from the availability of a three-dimensional X-ray-derived structure of acetylcholinesterase which allows for interpretations at an atomic level of resolution. Three distinct regions in the enzyme appear responsible for conferring selectivity the acyl pocket defined primarily by phenylalanines 295 and 297, the choline subsite primarily defined by tryptophan 86, tyrosine 337 and glutamate 202 and the peripheral anionic site defined by tryptophan 286, tyrosine 72, tyrosine 124 and aspartate 74. Through site-specific mutagenesis we have been able to modify acyl pocket specificity, selectivity toward neutral and charged substrates, substrate inhibition, organophosphate reactivity, organophosphate aging and oxime reactivation. These studies have important implications in developing superior antidotes for organophosphate poisoning and in using recombinant acetylcholinesterase as an antidote.
- HIGH RATE
- PHYSICAL PROPERTIES
- GENETIC ENGINEERING
- VOLUMETRIC ANALYSIS
- ATOMIC ENERGY LEVELS