title: The importance of glycine-30 for enzymatic activity of phospholipase A2.
abstract: The nearly conserved glycine-30 in porcine pancreatic phospholipase A2 has been replaced by serine. The resulting mutant G30S was expressed in Escherichia coli, purified and characterized. The mutation caused a significant drop in enzymatic activity towards monomeric and aggregated substrates, but had a limited effect on substrate binding. In contrast the affinity for calcium ions, the essential cofactor, was reduced 10-fold. The reduced enzymatic activity is attributed to a reduced stabilization of the transition state. The results are discussed in view of naturally occurring inactive phospholipase A2 homologues from snake venom.
authors.affiliation: Department of Enzymology and Protein Engineering, University of Utrecht, CBLE, University Centre De Uithof, The Netherlands.
authors.forename: A C
authors.initials: AC
authors.lastname: Bekkers
authors.forename: P A
authors.initials: PA
authors.lastname: Franken
authors.forename: E
authors.initials: E
authors.lastname: Toxopeus
authors.forename: H M
authors.initials: HM
authors.lastname: Verheij
authors.forename: G H
authors.initials: GH
authors.lastname: de Haas
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D005998:Glycine; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015345:Oligonucleotide Probes; D010179:Pancreas / Q000201:enzymology; D010741:Phospholipases A / Q000235:genetics / Q000378:metabolism*; D054467:Phospholipases A2; D015183:Restriction Mapping; D013379:Substrate Specificity; D013552:Swine
chemical_list: D015345:Oligonucleotide Probes; D010741:Phospholipases A; D054467:Phospholipases A2; D005998:Glycine