Linked Life Data

2742824

Source:http://linkedlifedata.com/resource/pubmed/id/2742824

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1989-8-25
pubmed:abstractText
3-Hydroxybutyrate dehydrogenase (BDH) is a lecithin-requiring mitochondrial enzyme which catalyzes the interconversion of 3-hydroxybutyrate and acetoacetate with NAD(H) as coenzyme. The purified enzyme devoid of lipid (i.e., the apodehydrogenase or apoBDH) can be reactivated with soluble lecithin or by insertion into phospholipid vesicles containing lecithin. Two different models have been proposed to explain the sigmoidal lipid activation curves. For both models, activation of BDH is assumed to require the binding of two lecithin molecules per functional unit. Activation of soluble enzyme (dimeric form) by short-chain (soluble) lecithin is consistent with a model in which lecithin binding is noncooperative, whereas activation of the membrane-bound enzyme (tetrameric form) indicates cooperativity between the lecithin binding sites. A new comprehensive model is presented in which lecithin is considered to be an essential allosteric activator that shifts the equilibrium between conformational states of the enzyme. Resonance energy transfer data, reflecting NADH binding to membrane-bound and soluble apoBDH, are consistent with such a lecithin-induced conformational change. Apparent dissociation constants for binding of NADH to BDH are approximately 10 microM and approximately 37 microM for BDH activated by bilayer and soluble lecithin, respectively. The maximal fluorescence resonance energy transfer (delta F max) increases with higher mole fraction of lecithin in the bilayer. The largest changes occur between mole fractions 0 and 0.13, thereby correlating with enzymic function. Essentially no binding of NADH is observed in the absence of lecithin.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3000-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Cooperativity in lipid activation of 3-hydroxybutyrate dehydrogenase: role of lecithin as an essential allosteric activator.
pubmed:affiliation
Department of Molecular Biology, Vanderbilt University, Nashville, Tennessee 37235.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.