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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2005-2-17
pubmed:abstractText
Myo-inositol monophosphate phosphatase (IMPP) is a key enzyme in the phosphoinositide cell-signaling system. This study found that incubating the IMPP from a porcine brain with pyridoxal-5'-phosphate (PLP) resulted in a time-dependent enzymatic inactivation. Spectral evidence showed that the inactivation proceeds via the formation of a Schiff's base with the amino groups of the enzyme. After the sodium borohydride reduction of the inactivated enzyme, it was observed that 1.8 mol phosphopyridoxyl residues per mole of the enzyme dimer were incorporated. The substrate, myo-inositol-1-phosphate, protected the enzyme against inactivation by PLP. After tryptic digestion of the enzyme modified with PLP, a radioactive peptide absorbing at 210 nm was isolated by reverse-phase HPLC. Amino acid sequencing of the peptide identified a portion of the PLP-binding site as being the region containing the sequence L-Q-V-S-Q-Q-E-D-I-T-X, where X indicates that phenylthiohydantoin amino acid could not be assigned. However, the result of amino acid composition of the peptide indicated that the missing residue could be designated as a phosphopyridoxyl lysine. This suggests that the catalytic function of IMPP is modulated by the binding of PLP to a specific lysyl residue at or near its substrate-binding site of the protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1225-8687
pubmed:author
pubmed:issnType
Print
pubmed:day
31
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
58-64
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:15715947-Amino Acids, pubmed-meshheading:15715947-Animals, pubmed-meshheading:15715947-Binding Sites, pubmed-meshheading:15715947-Borohydrides, pubmed-meshheading:15715947-Brain, pubmed-meshheading:15715947-Catalysis, pubmed-meshheading:15715947-Chromatography, High Pressure Liquid, pubmed-meshheading:15715947-Enzyme Activation, pubmed-meshheading:15715947-Inositol Phosphates, pubmed-meshheading:15715947-Lysine, pubmed-meshheading:15715947-Oxidation-Reduction, pubmed-meshheading:15715947-Peptide Fragments, pubmed-meshheading:15715947-Phenylthiohydantoin, pubmed-meshheading:15715947-Phosphoric Monoester Hydrolases, pubmed-meshheading:15715947-Protein Binding, pubmed-meshheading:15715947-Pyridoxal Phosphate, pubmed-meshheading:15715947-Swine, pubmed-meshheading:15715947-Time Factors
pubmed:year
2005
pubmed:articleTitle
Inactivation of brain myo-inositol monophosphate phosphatase by pyridoxal-5'-phosphate.
pubmed:affiliation
Department of Genetic Engineering and Research Institute for Bioscience and Biotechnology, Hallym University, Chunchon 200-702, Korea.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't