Linked Life Data

11744063

Source:http://linkedlifedata.com/resource/pubmed/id/11744063

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-12-17
pubmed:abstractText
Cystathionine beta-synthase is a key heme and pyridoxal phosphate-dependent enzyme involved in homocysteine metabolism in humans. The role of the recently discovered heme in this protein remains an important open question. The axial ligands to the heme in both the ferrous and ferric states have been assigned as cysteine and histidine residues, respectively. In this study, we have examined the effect of ligation and spin state changes in the heme on the activity of the enzyme. Treatment of the ferric enzyme with HgCl2 results in the conversion of six-coordinate low-spin heme to five-coordinate high-spin heme and is paralleled by a loss of activity. In contrast, treatment of the ferrous enzyme with HgCl2 results in replacement of the cysteine ligand by an unidentified sixth ligand and retention of the six-coordinate state, and is also accompanied by loss of enzyme activity. Treatment of the five-coordinate HgCl2-treated enzyme with thiols, such as homocysteine, results in reversion to a six-coordinate state. Resonance Raman spectroscopy with 34S-labeled enzyme reveals the return of the endogenous thiol ligand under these conditions and rules out direct coordination by the thiolate of homocysteine to the heme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0162-0134
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
87
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
253-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Mercuric chloride-induced spin or ligation state changes in ferric or ferrous human cystathionine beta-synthase inhibit enzyme activity.
pubmed:affiliation
Department of Biochemistry, University of Nebraska, Lincoln, NE 68588-0664, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't