Linked Life Data

4083900

Source:http://linkedlifedata.com/resource/pubmed/id/4083900

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1986-1-30
pubmed:abstractText
A radiochemical assay was developed for measuring branched-chain alpha-ketoacid dehydrogenase activity of Triton X-100 extracts of freeze-clamped rat liver. The proportion of active (dephosphorylated) enzyme was determined by measuring enzyme activities before and after activation of the complex with a broad-specificity phosphoprotein phosphatase. Hepatic branched-chain alpha-ketoacid dehydrogenase activity in normal male Wistar rats was 97% active but decreased to 33% active after 2 days on low-protein (8%) diet and to 13% active after 4 days on the same diet. Restricting protein intake of lean and obese female Zucker rats also caused inactivation of hepatic branched-chain alpha-ketoacid dehydrogenase complex. Essentially all of the enzyme was in the active state in rats maintained for 14 days on either 30 or 50% protein diets. This was also the case for rats maintained on a commercial chow diet (minimum 23% protein). However, maintaining rats on 20, 8, and 0% protein diets decreased the percentage of the active form of the enzyme to 58, 10, and 7% of the total, respectively. Fasting of chow-fed rats for 48 h had no effect on the activity state of hepatic branched-chain alpha-ketoacid dehydrogenase, i.e., 93% of the enzyme remained in the active state compared to 97% for chow-fed rats. However, hepatic enzyme of rats maintained on 8% protein diet was 10% active before starvation and 83% active after 2 days of starvation. Thus, dietary protein deficiency results in inactivation of hepatic branched-chain alpha-ketoacid dehydrogenase complex, presumably as a consequence of low hepatic levels of branched-chain alpha-ketoacids, established inhibitors of branched-chain alpha-ketoacid dehydrogenase kinase. With rats fed a low-protein diet and subsequently starved, inhibition of branched-chain alpha-ketoacid dehydrogenase kinase by branched-chain alpha-ketoacids generated as a consequence of endogenous proteolysis most likely promotes the greater branched-chain alpha-ketoacid dehydrogenase activity state.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:volume
243
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
542-55
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Physiological covalent regulation of rat liver branched-chain alpha-ketoacid dehydrogenase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't