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¹⁵N Nuclear Magnetic Resonance Studies of the Liver Alcohol Dehydrogenase-NAD⁺-Pyrazole Complex

Citation

Becker, Nancy Newton (1983) ¹⁵N Nuclear Magnetic Resonance Studies of the Liver Alcohol Dehydrogenase-NAD⁺-Pyrazole Complex. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/nnx8-q333. https://resolver.caltech.edu/CaltechTHESIS:09262018-161343127

Abstract

The structures of the liver alcohol dehydrogenase (LADH)-NAD+-pyrazole and LADH-NAD+-4-ethylpyrazole complexes were investigated by 15N nuclear magnetic resonance (NMR) spectroscopy. 15N chemical shifts were obtained for 15N-labeled inhibitors and 15N-labeled coenzyme bound in the enzyme ternary complexes. The structures of the two inhibitor complexes were found to be very similar. 15N chemical shifts of various pyrazole derivatives were determined. 15N NMR studies of model pyrazole derivative-zinc chloride complexes were carried out to determine the effect of zinc complexation on the pyrazole N2 chemical shift. The N1 nicotinarnide resonance of the coenzyme of the LADH-NAD+-pyrazole complex was 96 ppm upfield from that of NAD+ in solution and only 13 ppm downfield from that of NADH in solution, demonstrating formation of a derivative of dihydronicotinamide. The 15N chemical shift of the pyrazole N1 of the ternary complex when compared to other pyrazole derivatives indicated bond formation between pyrazole N1 and the nicotinarnide ring of the coenzyme. The 15N shift of the pyrazole N1 of the model pyrazole-NAD+ adduct, N-benzyl-1,4-dihydro-4-pyrazolylnicotinarnide, was 5.8 ppm downfield from that of N1 of the enzyme ternary complex. The 15N chemical shift of the pyrazole N2 of the ternary complex compared to pyrazole derivatives in solution was shielded by more than 40 ppm, demonstrating direct complexation of N2 to the active-site zinc. The results of model zinc complex studies indicated 60-100% inner-sphere coordination of the pyrazole N2 to the active-site zinc in the ternary complex.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Richards, John H.
Thesis Committee:
  • Roberts, John D. (chair)
  • Dougherty, Dennis A.
  • Campbell, Judith L.
  • Richards, John H.
Defense Date:12 April 1983
Record Number:CaltechTHESIS:09262018-161343127
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:09262018-161343127
DOI:10.7907/nnx8-q333
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11201
Collection:CaltechTHESIS
Deposited By: Melissa Ray
Deposited On:02 Oct 2018 18:15
Last Modified:16 Apr 2021 22:10

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