Linked Life Data

8463304

Source:http://linkedlifedata.com/resource/pubmed/id/8463304

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1993-5-6
pubmed:abstractText
The steady-state kinetic parameters for the phosphorylation of four peptides by the catalytic subunit of cAMP-dependent protein kinase were measured as a function of pH. For peptides containing the minimum consensus sequence, R-R-X-S-hyd (where hyd is a hydrophobic residue), the kcat/Kpeptide profile is bell-shaped with pK values of 6.4 and 9.4. Inhibition studies with the peptide LRRNAI indicate that the lower pK corresponds to an intrinsic pK on the enzyme, whereas the higher pK is perturbed upward by 1 pH unit. Viscosity studies verify that substrate stickiness accounts for the kinetic perturbation of the higher pK in kcat/Kpeptide. Substitution of the P-3 arginine with alanine (where serine is the P-site) yields a kcat/Kpeptide versus pH profile that is also bell-shaped, although both pK values are intrinsic acid dissociation constants of the enzyme. Replacement of the P-2 arginine with alanine removes the lower pK in the pH-rate profile without altering the higher pK. These results indicate that recognition of the P-2 arginine requires the ionization of an enzyme residue. This result implies that if the catalytic subunit mechanism involves general base catalysis, the ionization of this bse is not manifested in the pH-rate profiles.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
268
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7747-52
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Phosphorylation of peptide substrates for the catalytic subunit of cAMP-dependent protein kinase.
pubmed:affiliation
Department of Chemistry, University of California, San Diego, La Jolla 92093-0654.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.