Linked Life Data

2016289

Source:http://linkedlifedata.com/resource/pubmed/id/2016289

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1991-5-17
pubmed:abstractText
Binding of neopentylcobalamin and benzylcobalamin to the apoprotein of a haptocorrin from chicken serum has been demonstrated spectrophotometrically. The spectra of the protein-bound cobalamins strongly resemble those of base-on alkylcobalamins and show that when unbound these sterically hindered alkylcobalamins are only approximately 75% (benzyl) and 40% (neopentyl) base-on, at neutral pH and at 5 degrees C. The haptocorrin was found to stabilize the spontaneous thermal decomposition of the neutral species of benzylcobalamin and neopentylcobalamin by 470-fold (3.6 kcal) and 166-fold (3.0 kcal), respectively, relative to the protein-free species. After correction of the activation parameters for the thermal decomposition of the protein-free, neutral alkylcobalamins for the relative proportions of base-on and base-off species, the haptocorrin was found to stabilize the base-on species of both alkylcobalamins by 275- to 1400-fold (approximately 3.3 to 4.3 kcal). From the temperature dependence of the decomposition reactions, the enthalpies of activation are found to be essentially identical for the protein-free and protein-bound species of either cobalamin. Thus, stabilization of the thermal decomposition of these sterically hindered alkylcobalamins by haptocorrin is entirely due to entropic factors.
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
266
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6737-41
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Stabilization of thermally labile alkylcobalamins by a haptocorrin from chicken serum.
pubmed:affiliation
Department of Chemistry, Mississippi State University, Mississippi State 39762.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.