Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1991-7-2
pubmed:abstractText
Kinetic analysis has shown that isoquinoline, papaverine and berberine act as reversible competitive inhibitors to muscle lactate dehydrogenase and mitochondrial malate dehydrogenase with respect to the coenzyme NADH. The inhibitor constants Ki vary from 7.5 microM and 12.6 microM berberine interaction with malate dehydrogenase and lactate dehydrogenase respectively to 91.4 microM and 196.4 microM with papaverine action on these two enzymes. Isoquinoline was a poor inhibitor with Ki values of 200 microM (MDH) to 425 microM (LDH). No inhibition was observed for both enzymes in terms of their respective second substrate (oxaloacetic acid - malate dehydrogenase; pyruvate - lactate dehydrogenase). A fluorimetric analysis of the binding of the three alkaloids show that the dissociation constants (Kd) for malate dehydrogenase are 2.8 microM (berberine), 46 microM (papaverine) and 86 microM (isoquinoline); the corresponding values for lactate dehydrogenase are 3.1 microM, 52 microM and 114 microM. In all cases the number of binding sites averaged at 2 (MDH) and 4 (LDH). The binding of the alkaloids takes place at sites close to the coenzyme binding site. No conformational non equivalence of subunits is evident.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
8755-5093
pubmed:author
pubmed:issnType
Print
pubmed:volume
4
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
233-43
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Protein ligand interactions:isoquinoline alkaloids as inhibitors for lactate and malate dehydrogenase.
pubmed:affiliation
Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't