Sulfhydryl groups in relation to the structure and catalytic activity of 2-OXO-4-hydroxyglutarate aldolase from bovine liver
dc.contributor.author | Lane, Roger S. | en_US |
dc.contributor.author | Hansen, Barbara A. | en_US |
dc.contributor.author | Dekker, Eugene E. | en_US |
dc.date.accessioned | 2006-04-07T17:12:26Z | |
dc.date.available | 2006-04-07T17:12:26Z | |
dc.date.issued | 1977-03-15 | en_US |
dc.identifier.citation | Lane, Roger S., Hansen, Barbara A., Dekker, Eugene E. (1977/03/15)."Sulfhydryl groups in relation to the structure and catalytic activity of 2-OXO-4-hydroxyglutarate aldolase from bovine liver." Biochimica et Biophysica Acta (BBA) - Enzymology 481(1): 212-221. <http://hdl.handle.net/2027.42/22958> | en_US |
dc.identifier.uri | http://www.sciencedirect.com/science/article/B73GH-47SV4DJ-1P/2/11e259f6cb38d8cb6d199eb2e12273bd | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/22958 | |
dc.identifier.uri | http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=557345&dopt=citation | en_US |
dc.description.abstract | Bovine liver 2-oxo-4-hydroxyglutarate aldolase (suggested name: 2-oxo-4hydroxyglutarate glyoxylate-lyase catalyzing the reaction: 2-oxo-4-hydroxyglutarate rlhar2 pyruvate + glyoxylate) contains eight to ten sulfhydryl groups as determined by titration of the enzyme with either 5,5'-dithiobis(2-nitrobenzoic acid) (Nbs2) or p-mercuribenzoate in the presence of 1% sodium dodecyl sulfate. In the absence of a denaturant, all of the cysteinyl residues react with p-mercuribenzoate whereas only four are accessible to titration with Nbs2. No differences in -SH group reactivity can be detected during titration of the aldolase with p-mercuribenzoate. In contrast, two classes of sulfhydryls can be differentiated in the disulfide exchange reaction with Nbs2 in the absence of a denaturant; one -SH group (Class I) reacts rapidly whereas three additional thiols (Class II) titrate at approx. 0.1 the rate of the Class I -SH residue. Both pyruvate and glyoxylate protect one of the three -SH residues in Class II from reaction with Nbs2. Either substrate also prevents titration of one to two thiol groups by p-mercuribenzoate and decreases the rate of reaction of aldolase -SH groups with Nbs2 in 8 M urea. These ligand-induced changes in -SH reactivity provide a sensitive indication that the enzyme exists in an altered conformational state in the presence of either of its cosubstrates.Titration of the enzyme with either Nbs2 or p-mercuribenzoate results in a progressive loss of aldolase activity which is not proportional to the number of -SH groups modified. The enzyme retains 50% of the activity of the native enzyme when Class I and Class II thiols (i.e. four -SH groups total) are modified with Nbs2; 15% residual activity is still observed following titration of all of the cysteinyl residues with p-mercuribenzoate. Pyruvate and glyoxylate provide partial protection against inactivation. It is concluded that inactivation of 2-oxo-4-hydroxyglutarate aldolase by Nbs2 or p-mercuribenzoate is a consequence of alterations in protein structure which accompany modification of -SH groups. The data argue against the direct participation of an active-site thiol group in the catalytic mechanism of 2-oxo-4-hydroxyglutarate aldolase, be that aldol cleavage and condensation or [beta]-decarboxylation. | en_US |
dc.format.extent | 637498 bytes | |
dc.format.extent | 3118 bytes | |
dc.format.mimetype | application/pdf | |
dc.format.mimetype | text/plain | |
dc.language.iso | en_US | |
dc.publisher | Elsevier | en_US |
dc.title | Sulfhydryl groups in relation to the structure and catalytic activity of 2-OXO-4-hydroxyglutarate aldolase from bovine liver | en_US |
dc.type | Article | en_US |
dc.rights.robots | IndexNoFollow | en_US |
dc.subject.hlbsecondlevel | Materials Science and Engineering | en_US |
dc.subject.hlbsecondlevel | Chemistry | en_US |
dc.subject.hlbsecondlevel | Chemical Engineering | en_US |
dc.subject.hlbtoplevel | Science | en_US |
dc.subject.hlbtoplevel | Engineering | en_US |
dc.description.peerreviewed | Peer Reviewed | en_US |
dc.contributor.affiliationum | Department of Biological Chemistry, The University of Michigan, Ann Arbor, Mich. 48109, U.S.A.; Department of Biochemistry, State University of New York at Buffalo, Buffalo, N.Y. 14214, U.S.A. | en_US |
dc.contributor.affiliationum | Department of Biological Chemistry, The University of Michigan, Ann Arbor, Mich. 48109, U.S.A.; Department of Immunology, Rush Medical School, Chicago, Ill. 60612, U.S.A. | en_US |
dc.contributor.affiliationum | Department of Biological Chemistry, The University of Michigan, Ann Arbor, Mich. 48109, U.S.A | en_US |
dc.identifier.pmid | 557345 | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/22958/1/0000525.pdf | en_US |
dc.identifier.doi | http://dx.doi.org/10.1016/0005-2744(77)90153-X | en_US |
dc.identifier.source | Biochimica et Biophysica Acta | en_US |
dc.owningcollname | Interdisciplinary and Peer-Reviewed |
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