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dc.contributor.advisorMeyer, Edgar F.
dc.contributor.advisorSchweikert, Emile A.
dc.creatorTakahashi, Lori Hina
dc.date.accessioned2020-09-02T21:10:36Z
dc.date.available2020-09-02T21:10:36Z
dc.date.issued1987
dc.identifier.urihttps://hdl.handle.net/1969.1/DISSERTATIONS-747644
dc.descriptionTypescript (photocopy).en
dc.description.abstractElastase (EC 3.4.21.11) is normally involved in the degradation of elastin, and is believed to be the primary agent responsible for the induction of several degenerative connective tissue diseases. The primary subsite specificity of porcine pancreatic elastase (PPE) was mapped with a series of tetrapeptide amide substrates of the general formula Ac-Pro-Ala-Pro-X-NH₂, where X represented one of 7 amino acids. The kinetic results were compared to values predicted from molecular mechanics calculations (Presta, 1985) and previously reported kinetic studies. To further examine the interactions in the primary specificity subsite, three x-ray crystallographic studies were performed. First, 2.57 A resolution x-ray crystallographic data for the complex of Ac-Ala-Pro-Val-trifluoromethyl ketone with PPE were refined to R = 0.14. The inhibitor formed a stable, covalent, tetrahedral addition complex with the Oγ atom of the catalytic Ser-195. The second structure was the covalent enzyme-inhibitor complex of PPE with Ac-Ala-Pro-Val-difluoro-β-ketophenethylamide at 1.78 Å resolution (R = 0.16). As in the previous structure, the inhibitor formed a stable hemiketal intermediate with Oγ atom of Ser-195. An additional hydrogen bond between His-57N[epsilon] and one of the fluorines aided in stabilizing the complex. Both fluorinated inhibitors formed compounds which were structural mimics for the tetrahedral intermediate that is formed in the pathway for substrate hydrolysis. Thus, they can be regarded transition-state analogs. The last crystal structure was the complex of PPE with Cbz-Ala-Ile-boronic acid at 2.53 A resolution (R = 0.16). The mechanism of inhibition first involved a covalent bond with Oγ of Ser-195, followed by the loss of one of the boron hydroxyl atoms. The boron atom then becomes trigonal, but His-57 N[epsilon] makes a coordinate covalent bond (2.19 A) with the boron atom. The inclusion of His-57 in the mechanism of inhibition can explain the high potency of these inhibitors. The results from the synthesis and kinetics studies, in conjunction with those obtained from the crystallographic studies can give new information which can be used in the design of new medicinals targeted for elastase pathologies.en
dc.format.extentxii, 126 leavesen
dc.format.mediumelectronicen
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectMajor chemistryen
dc.subject.classification1987 Dissertation T136
dc.subject.lcshElastasesen
dc.subject.lcshInhibitorsen
dc.subject.lcshPeptidesen
dc.subject.lcshSynthesisen
dc.subject.lcshX-ray crystallographyen
dc.titleKinetic and crystallographic analysis of porcine pancreatic elastase-ligand interactionsen
dc.typeThesisen
thesis.degree.disciplineChemistryen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameDoctor of Philosophyen
thesis.degree.namePh. D. in Chemistryen
thesis.degree.levelDoctorialen
dc.contributor.committeeMemberRaushel, Frank
dc.contributor.committeeMemberWong, Chi-Huey
dc.type.genredissertationsen
dc.type.materialtexten
dc.format.digitalOriginreformatted digitalen
dc.publisher.digitalTexas A&M University. Libraries
dc.identifier.oclc18670808


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