Linked Life Data

235552

Source:http://linkedlifedata.com/resource/pubmed/id/235552

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1975-7-7
pubmed:abstractText
An enzyme that uses GTP as substrate for the formation in stoichiometric quantities of formate, inorganic pyrophosphate, and 2,5-diamino-6-hydroxy-4-(ribosylamino)pyrimidine-5'-phosphate has been purified 2200-fold from extracts of Escherichia coli B. This enzyme is named GTP cyclohydrolase II to distinguish it from a previously studied E. coli enzyme, named GTP cyclohydrolase (and called GTP cyclohydrolase I in this paper), that catalyzes the first of a series of enzymatic reactions leading to the biosynthesis of the pteridine portion of folic acid (Burg, A. W., and Brown, G. M. (1968) J. Biol. Chem. 243, 2349-2358). Some of the properties of GTP cyclohydrolase II are: (a) divalent cations are required for activity (Mg2+ is most effective); (b) its molecular weight, estimated by filtration on Sephadex G-200, is 44,000; (c) the K-m for GTP is 41 mum; (d) its pH optimum is 8.5; and (e) its activity is inhibited by inorganic pyrophosphate, one of the products of the reaction. Compounds not used as substrate are: GDP, GMP, guanosine, dGTP, ATP, ITP, and XTP. Properties a, b, c, and e (above), as well as the nature of the products, distinguish this enzyme from GTP cyclohydrolase I. Since GTP cyclohydrolase II apparently is not concerned with the biosynthesis of folic acid, the possible physiological role of this enzyme in the biosynthesis of riboflavin is considered in the light of the present investigations and the previously published work on riboflavin biosynthesis by other investigators.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
250
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3545-51
pubmed:dateRevised
2009-10-27
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Purification and properties of guanosine triphosphate cyclohydrolase II from Escherichia coli.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.