Linked Life Data

19758989

Source:http://linkedlifedata.com/resource/pubmed/id/19758989

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
45
pubmed:dateCreated
2009-11-2
pubmed:abstractText
Glycolate oxidase is a flavin-dependent, peroxisomal enzyme that oxidizes alpha-hydroxy acids to the corresponding alpha-keto acids, with reduction of oxygen to H(2)O(2). In plants, the enzyme participates in photorespiration. In humans, it is a potential drug target for treatment of primary hyperoxaluria, a genetic disorder where overproduction of oxalate results in the formation of kidney stones. In this study, steady-state and pre-steady-state kinetic approaches have been used to determine how pH affects the kinetic steps of the catalytic mechanism of human glycolate oxidase. The enzyme showed a Ping-Pong Bi-Bi kinetic mechanism between pH 6.0 and 10.0. Both the overall turnover of the enzyme (k(cat)) and the rate constant for anaerobic substrate reduction of the flavin were pH-independent at pH values above 7.0 and decreased slightly at lower pH, suggesting the involvement of an unprotonated group acting as a base in the chemical step of glycolate oxidation. The second-order rate constant for capture of glycolate (k(cat)/K(glycolate)) and the K(d)((app)) for the formation of the enzyme-substrate complex suggested the presence of a protonated group with apparent pK(a) of 8.5 participating in substrate binding. The k(cat)/K(oxygen) values were an order of magnitude faster when a group with pK(a) of 6.8 was unprotonated. These results are discussed in the context of the available three-dimensional structure of GOX.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
6
pubmed:volume
284
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
31214-22
pubmed:dateRevised
2010-11-9
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Involvement of ionizable groups in catalysis of human liver glycolate oxidase.
pubmed:affiliation
Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-4098, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.