Acetyl-L-alanyl-L-alanyl-L-alanine methyl ester: a new highly specific elastase substrate.
TL;DR: Acetyl-L-alanine methyl ester is a highly specific esteratic substrate for elastase, and can be used in crude preparations and for the study of proelastase activation.
Abstract: Acetyl-L-alanyl-L-alanyl-L-alanine methyl ester is a highly specific esteratic substrate for elastase. It is only slowly hydrolyzed by trypsin and α-chymotrypsin (0.13 and 1.2%, respectively, of the rate of elastase), and can be used in crude preparations and for the study of proelastase activation. At pH 8.0 and 25°, KM = 0.43 mM; kcat = 73 s−1 and is independent of pH between 7.5 and 10.5. Acetyl-L-alanine methyl ester is a poor substrate with KM 153 mM and kcat 6.7 s−1.
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