Linked Life Data

11067854

Source:http://linkedlifedata.com/resource/pubmed/id/11067854

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2001-5-23
pubmed:abstractText
Angiotensin (Ang) I-converting enzyme (ACE) is a member of the gluzincin family of zinc metalloproteinases that contains two homologous catalytic domains. Both the N- and C-terminal domains are peptidyl-dipeptidases that catalyze Ang II formation and bradykinin degradation. Multiple sequence alignment was used to predict His(1089) as the catalytic residue in human ACE C-domain that, by analogy with the prototypical gluzincin, thermolysin, stabilizes the scissile carbonyl bond through a hydrogen bond during transition state binding. Site-directed mutagenesis was used to change His(1089) to Ala or Leu. At pH 7.5, with Ang I as substrate, k(cat)/K(m) values for these Ala and Leu mutants were 430 and 4,000-fold lower, respectively, compared with wild-type enzyme and were mainly due to a decrease in catalytic rate (k(cat)) with minor effects on ground state substrate binding (K(m)). A 120,000-fold decrease in the binding of lisinopril, a proposed transition state mimic, was also observed with the His(1089) --> Ala mutation. ACE C-domain-dependent cleavage of AcAFAA showed a pH optimum of 8.2. H1089A has a pH optimum of 5.5 with no pH dependence of its catalytic activity in the range 6.5-10.5, indicating that the His(1089) side chain allows ACE to function as an alkaline peptidyl-dipeptidase. Since transition state mutants of other gluzincins show pH optima shifts toward the alkaline, this effect of His(1089) on the ACE pH optimum and its ability to influence transition state binding of the sulfhydryl inhibitor captopril indicate that the catalytic mechanism of ACE is distinct from that of other gluzincins.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4998-5004
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:11067854-Amino Acid Sequence, pubmed-meshheading:11067854-Angiotensin-Converting Enzyme Inhibitors, pubmed-meshheading:11067854-Animals, pubmed-meshheading:11067854-Asparagine, pubmed-meshheading:11067854-Binding Sites, pubmed-meshheading:11067854-COS Cells, pubmed-meshheading:11067854-Captopril, pubmed-meshheading:11067854-Catalysis, pubmed-meshheading:11067854-Histidine, pubmed-meshheading:11067854-Humans, pubmed-meshheading:11067854-Lisinopril, pubmed-meshheading:11067854-Metalloendopeptidases, pubmed-meshheading:11067854-Molecular Sequence Data, pubmed-meshheading:11067854-Peptidyl-Dipeptidase A, pubmed-meshheading:11067854-Protein Binding, pubmed-meshheading:11067854-Protein Structure, Tertiary, pubmed-meshheading:11067854-Recombinant Proteins, pubmed-meshheading:11067854-Sequence Homology, Amino Acid, pubmed-meshheading:11067854-Transfection
pubmed:year
2001
pubmed:articleTitle
Angiotensin I-converting enzyme transition state stabilization by HIS1089: evidence for a catalytic mechanism distinct from other gluzincin metalloproteinases.
pubmed:affiliation
Enzyme Research Unit, Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.