Size and Stereospecificity of the Active Site of Porcine Elastase

Daphne Atlas*, Arieh Berger

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Two diastereomeric groups of compounds, peptides of the general formula Ala4-Lys-Phe and Ala5-Lys-Phe and p-nitrobenzyl esters of tri-, tetra-, and pentaalanine residues, were synthesized and subjected to enzymic hydrolysis by porcine elastase. The bond cleaved in the peptide substrates is between Ala and Lys, and in the p-nitrobenzyl esters the ester bond is cleaved. By comparing ring Km and kcat values of the appropriate pairs of substrates, we can show that the active site of elastase extends over about 25 Å (seven sub-sites). Elastase does not catalyze the hydrolysis of esters of the d form, and stereospecificity decreases as the distance from the cleaved bond increases. When a D residue is placed at the N terminal of the substrate, no effect on the mode of binding (Km) or on the catalytic power (kcat) is observed.

Original languageEnglish
Pages (from-to)2573-2577
Number of pages5
JournalBiochemistry
Volume12
Issue number14
DOIs
StatePublished - 1 Jul 1973
Externally publishedYes

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