Linked Life Data

7696317

Source:http://linkedlifedata.com/resource/pubmed/id/7696317

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1995-5-2
pubmed:abstractText
The cDNA for coffee bean alpha-galactosidase (alpha-Gal) has been cloned and expressed in a baculovirus expression system. An early study of coconut alpha-Gal by chemical modification suggested that one tyrosine residue is at or near the active site. In order to identify such a critical residue, we replaced two tyrosine residues (positions 108 and 158) with phenylalanine by site-directed mutagenesis. The mutated DNA strands, as well as the wild-type ones, were subcloned into pVL vector and transformed into Sf9 insect cells for intracellular expression. The replacement of Tyr-158 with phenylalanine resulted in a mutant alpha-Gal (Y158F) which retained approx. 88% of the activity of wild-type enzyme. However, the substitution of Tyr-108 by phenylalanine (Y108F) almost abolished the enzymatic activity (1.8% of wild-type activity). The Vmax/Km value for the mutant Y108F was 0.027, which was over a 1000-fold lower than that of wild-type alpha-Gal. Our data suggest that Tyr-108 is critical for the enzymatic activity of alpha-Gal.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
1247
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
260-4
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Identification of tyrosine 108 in coffee bean alpha-galactosidase as an essential residue for the enzyme activity.
pubmed:affiliation
Lindsley F. Kimball Research Institute, New York Blood Center, NY 10021.
pubmed:publicationType
Journal Article