Linked Life Data

6309819

Source:http://linkedlifedata.com/resource/pubmed/id/6309819

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
1983-10-28
pubmed:abstractText
During net nucleoside triphosphate synthesis by chloroplast ATP synthase the extent of water oxygen incorporation into each nucleoside triphosphate released increases with decrease in ADP, GDP or IDP concentration. Likewise, during net ATP hydrolysis by the Mg2+-activated chloroplast ATPase, the extent of water oxygen incorporation into each Pi released increases as the ATP, GTP, or ITP concentration is decreased. However, the concentration ranges in which substrate modulation occurs differs with each nucleotide. Modulation of oxygen exchange during synthesis and hydrolysis of adenine nucleotides, as measured by variation in the extent of water oxygen incorporation into products, occurs below 250 microM. In contrast, guanosine and inosine nucleotides alter the extent of exchange at higher and much wider concentration ranges. Activation of the chloroplast ATPase by either heat or trypsin results in similar catalytic behavior as monitored by ATP modulation of oxygen exchanges during hydrolysis in the presence of Mg2+. More exchange capacity is evident with octylglucoside-activated enzyme at all ATP concentrations. High levels of tentoxin were also found to alter the catalytic exchange parameters resulting in continued water oxygen exchange into Pi released during hydrolysis at high ATP concentrations. Little or no oxygen exchange accompanies ATP hydrolysis in the presence of Ca2+. The [18O]Pi species formed from highly gamma-18O-labeled ATP at lower ATP concentrations gives a distribution as expected if only one catalytic pathway is operative at a given ATP concentration. This and other results support the concept of catalytic cooperativity between alternating sites as explanation for the modulation of oxygen exchange by nucleotide concentration.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/ATP Synthetase Complexes, http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate, http://linkedlifedata.com/resource/pubmed/chemical/Calcium, http://linkedlifedata.com/resource/pubmed/chemical/Glucosides, http://linkedlifedata.com/resource/pubmed/chemical/Magnesium, http://linkedlifedata.com/resource/pubmed/chemical/Multienzyme Complexes, http://linkedlifedata.com/resource/pubmed/chemical/Peptides, Cyclic, http://linkedlifedata.com/resource/pubmed/chemical/Phosphotransferases, http://linkedlifedata.com/resource/pubmed/chemical/Proton-Translocating ATPases, http://linkedlifedata.com/resource/pubmed/chemical/Trypsin, http://linkedlifedata.com/resource/pubmed/chemical/octyl-beta-D-glucoside, http://linkedlifedata.com/resource/pubmed/chemical/tentoxin
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10881-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Probes of catalytic site cooperativity during catalysis by the chloroplast adenosine triphosphate and the adenosine triphosphate synthase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.