Linked Life Data

6873612

Source:http://linkedlifedata.com/resource/pubmed/id/6873612

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1983-9-20
pubmed:abstractText
The mitochondrial enzyme heme synthase (ferrochelatase) catalyzes the formation of heme from ferrous iron and protoporphyrin. Using a fluorometric assay, the enzymatic formation of zinc-protoporphyrin in rat liver tissue was compared with heme formation. With sonicated liver homogenate, the rate of zinc-protoporphyrin formation was similar to that of heme when each metal was present alone in the reaction mixture. When combined in the reaction mixture, the two metals competed for the enzyme. With intact mitochondria, zinc was a better substrate, as 90% of the product was zinc-protoporphyrin in the presence of 50 microM zinc and 50 microM iron. The effect of zinc-protoporphyrin on the induction of delta-aminolevulinic acid synthase, the rate-limiting enzyme in hepatic heme biosynthesis, was also examined in the rat. Intraperitoneal injection of allylisopropylacetamide (350 mumol) induced activity of the enzyme fourfold. Concomitant administration of zinc-protoporphyrin (4 mumol) suppressed the induction by 52%, nearly as effectively as the same amount of heme. These findings indicate that the formation of zinc-protoporphyrin in liver may (a) inhibit the synthesis of heme and (b) exert negative feedback regulation on delta-aminolevulinic acid synthase. This combination would reduce the hepatic heme level.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0016-5085
pubmed:author
pubmed:issnType
Print
pubmed:volume
85
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
663-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Enzymatic formation of zinc-protoporphyrin by rat liver and its potential effect on hepatic heme metabolism.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.