Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1989-10-12
pubmed:abstractText
Adenylate kinase activity (ATP:AMP-phosphotransferase; EC 2.7.4.3) was studied in various subcellular fractions of rat brain tissues. Because of the presence of other adenosine nucleotide-utilizing enzymes, adenylate kinase activity was assayed in both the forward and reverse directions by using coupled enzyme systems and by using a specific adenylate kinase inhibitor, P1,P5-di(adenosine-5') pentaphosphate. As expected, the highest specific adenylate kinase activity (2.89 mumol/min/mg of protein) was detected in the cytosolic brain fraction. However, substantial enzyme activity (0.68 mumol/min/mg) was also found in the intact synaptosomal fraction isolated on Percoll/sucrose gradients. The increased specific enzyme activity of purified synaptosomes and the differences found between the kinetic parameters of the membrane-bound and cytosolic enzyme forms suggest that the synaptosomal adenylate kinase activity cannot be attributed to the small amount of contaminating cytosol present in our preparations. The adenylate kinase enzyme adhered to purified synaptic plasma membranes and was not released by washings with isoosmotic sucrose medium. The facts that the adenylate kinase enzyme activity could be measured in intact synaptosomal preparations and that both its substrates and its inhibitors do not cross intact plasma membranes support the possibility that the synaptosomal adenylate kinase is an ecto-enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-3042
pubmed:author
pubmed:issnType
Print
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1166-72
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Rat brain synaptosomal ATP:AMP-phosphotransferase activity.
pubmed:affiliation
Department of Neurology, UCLA Center for Health Sciences 90024.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.