Linked Life Data

3472524

Source:http://linkedlifedata.com/resource/pubmed/id/3472524

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1987-6-25
pubmed:abstractText
Phenol sulfotransferase (PST) catalyzes the sulfate conjugation of phenolic and catechol drugs and neurotransmitters. Human platelets and brain contain at least two forms of PST. One form is relatively thermolabile (TL) and catalyzes the sulfate conjugation of monoamines such as dopamine. The other is thermostable (TS) and catalyzes the sulfation of "simple" phenols such as phenol and p-nitrophenol. We found that homogenates of human liver also contain two forms of PST that are similar to brain and platelet TL and TS PST with regard to substrate specificities, thermal stabilities and sensitivities to inhibitors. Optimal conditions were determined for the assay of these two activities in human liver homogenates. The apparent Km of liver homogenate TL PST for dopamine was 27 microM. The apparent Km of the TS form of the enzyme for p-nitrophenol was 0.94 microM. Human liver TS PST also catalyzed the sulfate conjugation of dopamine, but with an apparent Km of 5 mM, over two orders of magnitude higher than that of TL PST. Two different peaks of TS PST activity were separated from the TL activity by ion exchange chromatography of human liver preparations. Both peaks of TS PST activity were partially purified and characterized. Both had similar substrate specificities and inhibitor sensitivities. Km values of TS PST peak I for p-nitrophenol and for 3'-phosphoadenosine-5'-phosphosulfate were 0.91 and 0.86 microM, respectively, while the Km values of TS PST peak II for these two cosubstrates for the reaction were 0.43 and 0.64 microM, respectively. However, the TS PST activity in peak II was significantly more thermolabile than was the activity in peak I. These results are compatible with the conclusion that human liver homogenates contain at least two forms of PST, forms with properties similar to those of TS and TL PST in homogenates of human cerebral cortex and platelets. In addition, human liver contains two isozymes of TS PST.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2952
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1435-46
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Human liver phenol sulfotransferase: assay conditions, biochemical properties and partial purification of isozymes of the thermostable form.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't