Linked Life Data

240687

Source:http://linkedlifedata.com/resource/pubmed/id/240687

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1975-12-30
pubmed:abstractText
Uridine diphospho-D-glucose (UDP-Glc) and UDP-methyl-D-glucuronate (UDP-GlcUAMe) have been shown to be competitive inhibitors for the UDP-apiose/udp-xylose synthase from cell suspension cultures of parsley. The apparent Ki values for these substrate analogues were of the same order of magnitude as the apparent Km value for the substrate UDP-D-glucuronic acid (UDP-GlcUA). The difference spectrum of the incubation mixture containing UDP-GlcUA, NAD+ and the highly purified enzyme showed a transient absorption with a maximum at 292 nm which disappeared upon addition of sodium hydroxide. The incubation with UDP-Glc or UDP-GlcUAMe also showed and NAD+-dependent absorption at 292 nm. However, in these cases a strong enhancement of the absorption at alkaline pH and a shift of the absorption maximum to longer wavelength were observed. Upon addition of 0-phenylenediamine to the enzyme incubation with UDP-Glc or UDP-GlcUAe a strong absorption with a maximum at respectively 335 and 315 nm appeared. The results show the transient formation of a 4-keto derivatives in the synthase reaction with the normal substrate UDP-GlcUA. The substrate analogues UDP-Glc and UDP-GlcUAMe can also be oxidized at C-4 by the enzyme in the presence of NAD+ to stable 4-keto derivatives which give rise to a strong absorption at alkaline pH or after reaction with o-phenylenediamine.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
493-8
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Spectroscopic evidence for the formation of a 4-keto intermediate in the UDP-apiose/UDP-xylose synthase reaction.
pubmed:publicationType
Journal Article