Linked Life Data

14678794

Source:http://linkedlifedata.com/resource/pubmed/id/14678794

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2003-12-17
pubmed:abstractText
Homogentisate 1,2-dioxygenase (HGD) is a mononuclear Fe(II)-dependent oxygenase that catalyzes the third step in the pathway for the catabolism of tyrosine, the conversion of homogentisate (HG) to maleylacetoacetate (MAA). We have heterologously expressed and purified native human HGD in the apo form. Steady-state analysis varying the concentration of both HG and molecular oxygen shows that the purified enzyme has a turnover number of 16 s(-1). Our data suggest that HG binds to the apo-enzyme and that the apo-HGD.HG complex does not bind Fe(II) and dissociates slowly at approximately 0.028 s(-1). The rate constant for the dissociation of Fe(II) from the holo-enzyme as measured under anaerobic conditions is 0.00004 s(-1) and indicates that this process is not relevant in steady-state turnover. The addition of HG and molecular oxygen to the holo-enzyme is formally random as the holo-enzyme reduces molecular oxygen at a rate of 1.35x10(3) M(-1) s(-1) at 4 degrees C. The term ordered with respect to the addition of substrates is most descriptive as the rate of reduction of molecular oxygen must increase in the presence of HG to sustain the observed turnover number.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
421
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
135-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Kinetic analysis of human homogentisate 1,2-dioxygenase.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211-3029, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't