Distinct cleavage specificity of human cathepsin E at neutral pH with special preference for Arg-Arg bonds.
In order to clarify the potential role of cathepsin E at neutral pH, the cleavage specificity of human cathepsin E was examined at pH 7.4 toward reduced-carboxymethylated(RCm-)ribonuclease A and various bioactive and related peptides. The specificity of the enzyme at pH 7.4 was found to be considerably different from that at acidic pH; preferential cleavages were observed with Arg-X and Glu-X bonds, which are not the major cleavage sites at acidic pH. Moreover, the Arg-Arg bond was found to be the most preferential site of cleavage. This unique specificity observed at pH 7.4 suggests the possibility that cathepsin E might be involved in processing and/or degradation of certain proteins and/or peptides at or near neutral pH in vivo.
School of Life Science, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan.
Senarath B P
SB
Athauda
Kenji
K
Takahashi
D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry / Q000378:metabolism*; D020059:Cathepsin E / Q000378:metabolism*; D005753:Gastric Mucosa / Q000201:enzymology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010455:Peptides / Q000378:metabolism*; D012259:Ribonuclease, Pancreatic / Q000378:metabolism*; D013379:Substrate Specificity
D010455:Peptides; D001120:Arginine; D012259:Ribonuclease, Pancreatic; D020059:Cathepsin E