Linked Life Data

16212382

Source:http://linkedlifedata.com/resource/pubmed/id/16212382

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2005-10-10
pubmed:abstractText
The zinc(II) complex (PATH)ZnOH, where PATH is an N2S(thiolate) ligand, has been investigated for its ability to promote the hydrolysis of the phosphate triester tris(4-nitrophenyl) phosphate (TNP). The hydrolysis of TNP was examined as a function of PATH-zinc(II) complex concentration, substrate concentration, and pH in a water/ethanol mixture (66:33 v/v) at 25 degrees C. The reaction is first order in both zinc(II) complex and substrate, and the second-order rate constants were derived from linear plots of the observed pseudo-first-order rate constants versus zinc complex concentration at different pH values. A pH-rate profile yielded a kinetic pK(a) of 8.52(5) for the zinc-bound water molecule and a pH-independent rate constant of 16.1(7) M(-1) s(-1). Temperature-dependent studies showed linear Eyring behavior, yielding the activation parameters DeltaH++ = 36.9(1) kJ mol(-1) and DeltaS++ = -106.7(4) J mol(-1) K(-1). Interpretation of the kinetic data leads to the conclusion that hydrolysis of TNP takes place through a hybrid mechanism, in which the metal center plays a dual role of providing a nucleophilic hydroxide and activating the substrate through a Lewis acid effect. The synthesis and structural characterization of the related nickel(II) and iron(II) complexes [(PATH)2Ni2]Br2 (2) and (PATH)2Fe2Cl2 (3) are also described. Taken together, these data suggest a possible explanation for the low reactivity of the zinc(II) form of peptide deformylase as compared to the iron(II) form.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0020-1669
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7559-69
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Phosphate triester hydrolysis promoted by an N2S(thiolate)Zn complex: mechanistic implications for the metal-dependent reactivity of peptide deformylase.
pubmed:affiliation
Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA. dpg@jhu.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural