Linked Life Data

3816020

Source:http://linkedlifedata.com/resource/pubmed/id/3816020

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1987-4-7
pubmed:abstractText
Sparteine metabolism was studied in human liver microsomes from nine extensive ([EM] urinary metabolic ratio [MR] less than 20) and four poor metabolizers ([PM] MR greater than 20). The formation of 2- and 5-dehydrospartein displayed monophasic Michaelis-Menten kinetics. In livers from PMs the formation of the major sparteine metabolite 2-dehydrosparteine was characterized by more than a thirtyfold increase in Michaelis-Menten constant (Km)(1880 +/- 1044 mumol/L) as compared with EM subjects with an MR less than 1 (58.3 +/- 38.8 mumol/L). EM subjects with an MR greater than 3 who may constitute heterozygous metabolizers showed Km values in between (658 +/- 301 mumol/L). There was no difference in maximum rate of metabolism (Vmax) of 2-dehydrosparteine formation between EM and PM subjects (101 +/- 39 vs. 86 +/- 52 pmol/min/mg). The formation of 5-dehydrosparteine exhibited a Km of 100 +/- 123 mumol/L similar to the Km of 2-dehydrosparteine formation. The urinary MR correlated positively with the Km for 2-dehydrosparteine formation. The intrinsic clearance for 2-dehydrosparteine showed a highly significant negative correlation with the MR. The pronounced differences in Km together with the significant correlation between Km and MR with no marked differences in Vmax between phenotypes suggest that the impaired oxidation capacity in PM subjects is more likely the result of a P-450 isozyme with altered catalytic properties rather than a decreased amount of enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0009-9236
pubmed:author
pubmed:issnType
Print
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
320-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Evidence for altered catalytic properties of the cytochrome P-450 involved in sparteine oxidation in poor metabolizers.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't