Study of the function of pyridoxal 5'-phosphate in glycogen phosphorylase

dc.contributor.author Chang, Yen-Chung
dc.contributor.department Biochemistry, Biophysics and Molecular Biology
dc.date 2018-08-15T16:11:01.000
dc.date.accessioned 2020-07-02T06:10:26Z
dc.date.available 2020-07-02T06:10:26Z
dc.date.copyright Sun Jan 01 00:00:00 UTC 1984
dc.date.issued 1984
dc.description.abstract <p>Phosphorylase reconstituted with pyridoxal, 6-fluoro-pyridoxal (6-FPAL), and 6-fluoropyridoxal phosphate (6-FLPL) were studied in this dissertation work to gain more insight of the involvement of the 5'-phosphoryl, 3-OH, and 1-nitrogen groups of pyrodoxal 5'-phosphorylase (PLP) in the catalytic process of glycogen phosphorylase. And the conformational changes around the coenzyme binding site during the "T state" (DBLARR) "R state" transition of glycogen phosphorylase was also examined;An analysis of apparent kinetic parameters of varied anions for the activation of pyridoxal phosphorylase and ('19)F NMR spectral study of the interaction between fluorophosphate and pyridoxal enzyme suggested that the 5'-phosphoryl group of enzyme-bound PLP does not affect the binding of glucose-1-P to the enzyme, that this phosphoryl group is unlikely to participate in any acid-base reaction essential for catalysis, and that the phosphoryl group could be distorted into a trigonal-bipyramidal geometry during catalysis, and that the phosphoryl group could be distorted into a trigonal-bipyramidal geometry during catalysis. Kinetic and NMR, UV-VIS, and fluorescence spectral studies of phosphorylase reconstituted with 6-FPAL and 6-FPLP reconfirmed that the enzyme-bound PLP is a neutral enolimine tautermer and suggested that the proton of the 3-OH in PLP is unlikely to be involved in any proton shuttle during catalysis. However, the ring nitrogen of PLP may interact with the protein, and this interaction may be important for efficient catalysis. Studies of nuclear relaxation mechanisms of the fluorine nucleus in 6-FPAL and 6-FPLP enzymes indicated that the protein structure around the coenzyme bind site undergoes substantial changes during the "T" to "R" transition. In the "R" state phosphorylase, the coenzyme is bound more tightly to the protein than in the "T" state enzyme, and the configuration of PLP, the relative orientation of the 5'-phosphate and 6-proton of the coenzyme, could be different in these two conformers.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/8980/
dc.identifier.articleid 9979
dc.identifier.contextkey 6347500
dc.identifier.doi https://doi.org/10.31274/rtd-180813-8941
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/8980
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/82028
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/8980/r_8423625.pdf|||Sat Jan 15 02:19:42 UTC 2022
dc.subject.disciplines Biology
dc.subject.keywords Biochemistry and biophysics
dc.subject.keywords Biochemistry
dc.title Study of the function of pyridoxal 5'-phosphate in glycogen phosphorylase
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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