Linked Life Data

3417662

Source:http://linkedlifedata.com/resource/pubmed/id/3417662

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
26
pubmed:dateCreated
1988-10-19
pubmed:abstractText
Rat liver glycine methyltransferase, a homotetramer, exhibits sigmoidal rate behavior with respect to S-adenosylmethionine (Ogawa, H., and Fujioka, M. (1982) J. Biol. Chem. 257, 3447-3452). The binding experiment shows that the sigmoidicity observed in initial velocity kinetics is explained by the cooperative binding of S-adenosylmethionine to the catalytic sites residing on each subunit. Limited proteolysis of glycine methyltransferase with trypsin in the presence of S-adenosylmethionine yields an enzyme lacking the NH2-terminal 8 residues. The proteolytically modified enzyme retains a tetrameric structure. The truncated enzyme shows no cooperativity with respect to S-adenosylmethionine binding and kinetics. It has values of Vmax and Km for glycine identical to those of the native enzyme, but a 3-fold lower [S]0.5 value for S-adenosylmethionine. The proteolytic modification is without effect on the circular dichroism and fluorescence spectra. Furthermore, the protein fluorescence of the modified enzyme is quenched upon addition of S-adenosylmethionine to the same extent as observed with the native enzyme. These results suggest that a short NH2-terminal segment, which lies outside the active site, is important for communication between subunits.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
263
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13381-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Rat liver glycine methyltransferase. Cooperative binding of S-adenosylmethionine and loss of cooperativity by removal of a short NH2-terminal segment.
pubmed:affiliation
Department of Biochemistry, Toyama Medical and Pharmaceutical University Faculty of Medicine, Japan.
pubmed:publicationType
Journal Article