Linked Life Data

656435

Source:http://linkedlifedata.com/resource/pubmed/id/656435

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1978-8-14
pubmed:abstractText
Human prostatic acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) is a dimeric (alpha 2) protein that catalyses the hydrolysis of phosphomonoesters. Several reports suggest that a phosphoenzyme intermediate is involved in the mechanism of acid phosphatase. Chemical modification studies and trapping experiments were therefore undertaken in order to ascertain the identity of the amino acid residue(s) involved in the formation of this intermediate. Human prostatic acid phosphatase is inactivated by diethyl pyrocarbonate (second-order rate constant of 7 M-1. min-1 at pH 6.2) with an accompanying increase in absorbance at 242 nm due to formation of ethoxyformylhistidyl derivatives. In the presence of competive inhibitors the rate of inactivation is decreased. Inactivation can be partially reversed by hydroxylamine. The pH curve of inactivation indicates the involvement of a residue having a pK alpha of 6.5. Direct evidence for the involvement of a histidine residue in the mechanism was obtained by trapping a covalent phosphohistidyl-enzyme intermediate. Incubation of the enzyme with p-nitrophenyl [32 P] phosphate leads to incorporation of 0.44 mol 32P/mol enzyme. The denatured phosphoenzyme,which was acid labile but base stable, was hydrolyzed in 3 M KOH and the radioactivity was found to cochromatograph with synthetic tau-phosphohistidine on Dowex-1 ion-exchange resin. These results are consistent with a catalytic mechanism involving histidine as a nucleophile in the formation of a covalents phosphoenzyme intermediate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
523
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
407-21
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1978
pubmed:articleTitle
An essential active-site histidine residue in human prostatic acid phosphatase. Ethoxyformylation by diethyl pyrocarbonate and phosphorylation by a substrate.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.