The two sides of enzyme-substrate specificity: lessons from the aspartic proteinases.
Like most proteolytic enzymes, the aspartic proteinases bind substrates and most inhibitors within an extended active site cleft. Bound ligands typically adopt a beta-strand conformation. Interactions with groups on both sides of the cleft determine the primary as well as secondary specificity of the enzymes. We have pursued the discovery of the sometimes subtle distinctions between members of the aspartic proteinase family by two routes. In the first case, we have constructed sets of oligopeptide substrates with systematic variation in each position to assess interactions at one position at a time. In the second type of experiment, we have altered residues of the enzymes in order to test theories of selectivity. The combination of the two approaches has provided a better understanding of the forces involved in determining specificity of enzyme action.
Dunn
B M
BM
Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, P.O. Box 100245, Gainesville, FL 32610-0245, USA.
Hung
S
S
D000595:Amino Acid Sequence; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002402:Cathepsin D / Q000378:metabolism; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism*; D010434:Pepsin A / Q000378:metabolism; D015800:Protozoan Proteins; D013379:Substrate Specificity
D009842:Oligopeptides; D015800:Protozoan Proteins; D016282:Aspartic Acid Endopeptidases; D010434:Pepsin A; C100637:plasmepsin II; D002402:Cathepsin D