Linked Life Data

3729412

Source:http://linkedlifedata.com/resource/pubmed/id/3729412

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1986-8-20
pubmed:abstractText
Studies in reconstituted systems indicate that the interconversions of proline and delta 1-pyrroline-5-carboxylate can constitute a shuttle which transfers reducing equivalents into mitochondria as proline and oxidizing potential out as delta 1-pyrroline-5-carboxylate. The studies reported here determine if the transfer of reducing equivalents can be stoichiometrically greater than the utilization of shuttle intermediates. First, 3HOH production from [5-3H]proline was used to quantitate proline oxidation under conditions where delta 1-pyrroline-5-carboxylate could recycle back to proline in a system containing mitochondrial particles and pyrroline-5-carboxylate reductase. In parallel incubations the metabolic fate of [U-14C]proline was determined. 3HOH production continued to increase while no net change occurred in 14C-labeled proline and delta 1-pyrroline-5-carboxylate indicating catalytic activity in this system. In another system that contained intact mitochondria and pyrroline-5-carboxylate reductase, proline oxidation was quantitated by both [U-14C]proline recoveries and 3HOH production from [5-3H]proline. Proline oxidation was the same by both methods in incubations lacking NADPH and pyrroline-5-carboxylate reductase. However, it was significantly underestimated by [U-14C]proline recoveries as compared to 3HOH production in incubations containing all shuttle components. These results indicate catalytic functioning of the proposed shuttle in a reconstituted system containing intact mitochondria. This shuttle may function at specific times to catalytically generate cytosolic NADP+ and in turn regulate enzymes limited by [NADP+]. We suggest that the proposed shuttle may function to increase ribose-5-phosphate synthesis by the oxidative limb of the pentose phosphate pathway and inturn increase PP-ribose-P and purine synthesis during the initiation of cell growth.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:volume
248
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
166-74
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Catalytic transfer of hydride ions from NADPH to oxygen by the interconversions of proline and delta 1-pyrroline-5-carboxylate.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.