Linked Life Data

3688482

Source:http://linkedlifedata.com/resource/pubmed/id/3688482

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1988-1-12
pubmed:abstractText
Round spermatids (steps 1-8) were isolated from rat testes and kinetic properties of pyruvate (PK) in their extract were examined. A plot of PK activity against phosphoenolpyruvate (PEP) or ADP concentration appeared sigmoidal. Km values for PEP and ADP were 0.12 and 0.29 mM, respectively. However, fructose 1,6-bisphosphate (FBP) stimulated the enzyme markedly by increasing its affinity for PEP. FBP (0.35 microM) was required for 50% activation of PK, when the PK activity was measured at 25 microM PEP and 0.2 mM ADP. In contrast, ATP (Ki = 6.5 mM) inhibited the PK activity. On the other hand, in the presence of 5 mM glucose, the level of FBP in spermatids increased markedly, while that of ATP declined rapidly. The level of ADP remained constant. When the activity of PK in spermatid extract was measured at intracellular levels of FBP, ADP and ATP, it was maximum. The results suggest that PK becomes probably fully activated when glucose is metabolized in the glycolytic pathway of spermatids. It seems unlikely that PK is the rate-limiting step in glycolysis of spermatids.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0303-4569
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
91-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:articleTitle
Metabolism of round spermatids: kinetic properties of pyruvate kinase.
pubmed:affiliation
Department of Obstetrics and Gynecology, School of Medicine, Teikyo University, Tokyo, Japan.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro