Linked Life Data

7819202

Source:http://linkedlifedata.com/resource/pubmed/id/7819202

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-2-16
pubmed:abstractText
On the basis of chemical modification studies, it was postulated that glutamate 268 was a component of the active site of liver aldehyde dehydrogenase [Abriola, D. P., Fields, R., MacKerell, A. D., Jr., & Pietruszko, R. (1987) Biochemistry 26, 5679-5684]. To study its role, the residue in human liver mitochondrial (class 2) aldehyde dehydrogenase was mutated to an aspartate, a glutamine, or a lysine, and the enzyme was expressed in Escherichia coli. The mutations did not affect the Km values for NAD or propionaldehyde, but grossly affected the catalytic activity of the enzymes when compared to recombinantly expressed native enzyme; the mutant enzymes had less that 0.4% of the specific activity of the recombinantly expressed native aldehyde dehydrogenase. The mutations also caused a long lag phase to occur prior to the steady state phase of the reaction. The activity of the mutant enzymes could not be restored by the addition of general bases such as sodium acetate, sodium formate, or imidazole. The Kd for NADH was essentially identical for the E268Q mutant and native enzyme. The three mutant forms of the enzyme possessed less than 0.8% of the esterolytic activity of the recombinantly expressed native enzyme. Pre-steady state analysis showed that there was no burst of NADH formation in the dehydrogenase reaction or of p-nitrophenol formation in the esterase reaction. This can be interpreted as implying that glutamate 268 may function as a general base necessary for the initial activation of the essential cysteine residue (302), rather than being involved in only the deacylation or hydride transfer step.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
237-43
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Involvement of glutamate 268 in the active site of human liver mitochondrial (class 2) aldehyde dehydrogenase as probed by site-directed mutagenesis.
pubmed:affiliation
Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.