Linked Life Data

1322897

Source:http://linkedlifedata.com/resource/pubmed/id/1322897

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1992-9-10
pubmed:abstractText
A 55-kDa form of membrane-associated phosphatidylinositol 4-kinase (ATP:phosphatidylinositol 4-phosphotransferase, EC 2.7.1.67) was purified 10,166-fold from Saccharomyces cerevisiae. The purification procedure included solubilization of microsome membranes with 1% Triton X-100 followed by chromatography with DE52, hydroxylapatite I, Q-Sepharose, Mono Q, and hydroxylapatite II. The procedure resulted in a nearly homogeneous 55-kDa phosphatidylinositol 4-kinase preparation. The 55-kDa phosphatidylinositol 4-kinase and the previously purified 45-kDa phosphatidylinositol 4-kinase differed with respect to their amino acid composition, isoelectric points, and peptide maps. Furthermore, the two forms of phosphatidylinositol 4-kinase did not show an immunological relationship. Maximum 55-kDa phosphatidylinositol 4-kinase activity was dependent on magnesium (10 mM) or manganese (0.5 mM) ions and Triton X-100 at the pH optimum of 7.0. The activation energy for the reaction was 12 kcal/mol, and the enzyme was labile above 30 degrees C. The enzyme was inhibited by thioreactive agents, MgADP, and calcium ions. A detailed kinetic analysis of the purified enzyme was performed using Triton X-100/phosphatidylinositol-mixed micelles. 55-kDa phosphatidylinositol 4-kinase activity followed saturation kinetics with respect to the bulk and surface concentrations of phosphatidylinositol and followed surface dilution kinetics. The interfacial Michaelis constant (Km) and the dissociation constant (Ks) for phosphatidylinositol in the Triton X-100 micelle surface were 1.3 mol % and 0.035 mM, respectively. The Km for MgATP was 0.36 mM. 55-kDa phosphatidylinositol 4-kinase catalyzed a sequential reaction mechanism as indicated by the results of kinetic and isotopic exchange reactions. The enzyme bound to phosphatidylinositol before ATP and released phosphatidylinositol 4-phosphate before ADP. The enzymological and kinetic properties of the 55-kDa phosphatidylinositol 4-kinase differed significantly from those of the 45-kDa phosphatidylinositol 4-kinase. This may suggest that the two forms of phosphatidylinositol 4-kinase from S. cerevisiae are regulated differentially in vivo.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
267
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16297-304
pubmed:dateRevised
2007-12-11
pubmed:meshHeading
pubmed-meshheading:1322897-1-Phosphatidylinositol 4-Kinase, pubmed-meshheading:1322897-Amino Acids, pubmed-meshheading:1322897-Chromatography, pubmed-meshheading:1322897-Chromatography, DEAE-Cellulose, pubmed-meshheading:1322897-Chromatography, Ion Exchange, pubmed-meshheading:1322897-Detergents, pubmed-meshheading:1322897-Durapatite, pubmed-meshheading:1322897-Enzyme Activation, pubmed-meshheading:1322897-Hydroxyapatites, pubmed-meshheading:1322897-Kinetics, pubmed-meshheading:1322897-Microsomes, pubmed-meshheading:1322897-Molecular Weight, pubmed-meshheading:1322897-Octoxynol, pubmed-meshheading:1322897-Phosphotransferases, pubmed-meshheading:1322897-Polyethylene Glycols, pubmed-meshheading:1322897-Saccharomyces cerevisiae, pubmed-meshheading:1322897-Saccharomyces cerevisiae Proteins, pubmed-meshheading:1322897-Thermodynamics
pubmed:year
1992
pubmed:articleTitle
Purification, characterization, and kinetic analysis of a 55-kDa form of phosphatidylinositol 4-kinase from Saccharomyces cerevisiae.
pubmed:affiliation
Department of Food Science, Cook College, Rutgers University, New Brunswick, New Jersey 08903.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't