Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2009-7-7
pubmed:abstractText
l-Threonine dehydrogenase, a key enzyme in the l-threonine metabolism, catalyses the NAD(+)-dependent conversion of l-threonine to 2-amino-3-ketobutyrate, that non-enzymically decarboxylates to aminoacetone. A search of the genome sequence of hyperthermophilic archaeon, Thermococcus kodakaraensis revealed the presence of a closely related orthologue (TK0916) of archaeal and bacterial l-threonine dehydrogenase genes. Expression in Escherichia coli, purification and characterization of the TK0916 gene product revealed that this gene actually coded for a protein with high levels of l-threonine dehydrogenase activity (7.26 U mg(-1)). The enzyme exhibited highest activity at pH 12 and 90 degrees C. The K(m) values for l-threonine and NAD(+) at 50 degrees C were 1.6 mM and 0.028 mM, respectively. The enzyme activity was dependent on divalent cations. The half-life of the enzyme was more than 2 h at 85 degrees C and 24 min in boiling water. This is the most thermostable threonine dehydrogenase exhibiting optimal activity at the highest pH (12) reported to date. This is the first report on the characterization of a TDH from genus Thermococcus.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1756-2651
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
146
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
95-102
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Highly thermostable L-threonine dehydrogenase from the hyperthermophilic archaeon Thermococcus kodakaraensis.
pubmed:affiliation
University of the Punjab, Lahore, Pakistan.
pubmed:publicationType
Journal Article, Comparative Study