Modification of aspartate aminotransferase with heavy atoms and with coenzyme analogs

dc.contributor.author Schmidt, Jane
dc.contributor.department Biochemistry, Biophysics and Molecular Biology
dc.date 2018-08-15T18:04:42.000
dc.date.accessioned 2020-07-02T05:56:20Z
dc.date.available 2020-07-02T05:56:20Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 1980
dc.date.issued 1980
dc.description.abstract <p>Aspartate aminotransferase forms large well-formed crystals on slow concentration by vapor diffusion against solutions of polyethylene glycol. Native enzyme and enzyme blocked at one or both of its surface sulfhydryls with small uncharged substituents were crystallized under the same conditions with methylmercuric chloride, p-chloromercuribenzoate or mercuric acetate in attempts to provide heavy atom derivative crystals. Methylmercury binds to cysteine-191 and cysteine-82 in both native AAT and the enzyme blocked with N-ethylmaleimide. Mercuribenzoate binds to cysteine-82 and cysteine-45 in the native enzyme. Native AAT has been crystallized with 2 equivalents per monomer of methylmercuric chloride or p-chloromercuribenzoate to provide two heavy atom derivative crystals for the crystallographic structure determination;Pyridoxal 5'-sulfate reacts at the active site of aspartate apoaminotransferase to modify lysine-258. Three peptides containing lysine-258 modified by pyridoxal sulfate have been isolated and characterized. The second nucleophilic group involved in the reaction of pyridoxal sulfate with the enzyme remains unidentified. It is most likely the hydroxyl of serine-257, but the guanidino group of arginine-386 and a hydroxide from the solvent are also possibilities;The 5'trans-carboxyethenyl analog of pyridoxal phosphate appears to modify the same active site peptides as pyridoxal sulfate.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/6760/
dc.identifier.articleid 7759
dc.identifier.contextkey 6293380
dc.identifier.doi https://doi.org/10.31274/rtd-180813-3578
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/6760
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/79563
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/6760/r_8019662.pdf|||Sat Jan 15 01:27:59 UTC 2022
dc.subject.disciplines Biochemistry
dc.subject.keywords Biochemistry and biophysics
dc.subject.keywords Biochemistry
dc.title Modification of aspartate aminotransferase with heavy atoms and with coenzyme analogs
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication faf0a6cb-16ca-421c-8f48-9fbbd7bc3747
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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