Linked Life Data

2790001

Source:http://linkedlifedata.com/resource/pubmed/id/2790001

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
1989-11-22
pubmed:abstractText
Substrate activation of the rate of the NAD-malic enzyme reaction by malate is obtained in the presence but not in the absence of oxalate. The substrate activation is a result of competition between malate and oxalate for the E.NADH complex, with malate binding to the form of the complex unprotonated at an enzyme group with a pK of 4.9 and oxalate binding preferentially to the protonated form. The off-rate for NADH from the E.NADH complex is completely rate limiting when the group with a pK of 4.9 is protonated but is only one of several rate-limiting steps when it is unprotonated [Kiick, D.M., Harris, B.G., & Cook, P.F. (1986) Biochemistry 25, 227]. The competition by malate with oxalate thus results in an overall increase in the off-rate for NADH as a result of binding to the unprotonated form of E.NADH. Consistent with the proposed mechanism, the deuterium isotope effect on V for the nonsubstrate-activating malate concentration range decreases from 1.6 in the absence of oxalate to 1.3 in the presence of a concentration of oxalate equal to its Kii. The rate equation for the oxalate-induced substrate activation by malate is derived and presented in the Appendix. Data are discussed in terms of the overall mechanism of the NAD-malic enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6334-40
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Substrate activation by malate induced by oxalate in the Ascaris suum NAD-malic enzyme reaction.
pubmed:affiliation
Department of Biochemistry, Texas College of Osteopathic Medicine, Fort Worth.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't