Linked Life Data

8186239

Source:http://linkedlifedata.com/resource/pubmed/id/8186239

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-6-21
pubmed:abstractText
Incubation of C4 NADP-malic enzyme from maize leaves with the oxidant o-iodosobenzoate leads to the reversible and complete inactivation of the enzyme. The time-course of inactivation is biphasic with the rate depending on the o-iodosobenzoate concentration. The inactivation is partially prevented by L-malate, NADP and Mg2+ alone, while NADP plus Mg2+ afford total protection. The complete reversal of the inactivation by the reductive agents dithiothreitol and 2-mercaptoethanol suggests that the modification of the enzyme by o-iodosobenzoate occurs concomitant with the oxidation of one or more pairs of sulfhydryl groups to the disulfide state, producing a conformationally altered form of the protein or directly modifying the active site. Titration of free thiol groups before and after inactivation of maize malic enzyme by o-iodosobenzoate shows a decrease in the accessible groups from 7 to 5, suggesting inactivation is accompanied by oxidation of two vicinal thiols. The oxidized form of the enzyme is rapidly reactivated by incubation with chemical and photochemically reduced thioredoxin in vitro, while the 'dark' activity of the enzyme is enhanced to the level of the 'light' activity by dithiothreitol. This evidence suggests that a reversible reduction and oxidation of disulfide bonds may take place during the regulation of the enzyme, indicating that the redox state of the disulfide bonds of C4 NADP-malic enzyme from maize leaves is important for the expression of maximal catalytic activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
1206
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10-6
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Redox regulation of maize NADP-malic enzyme by thiol-disulfide interchange: effect of reduced thioredoxin on activity.
pubmed:affiliation
Centro de Estudios Fotosintéticos y Bioquímicos, CONICET F.M. Lillo Universidad Nacional de Rosario, Argentina.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't