They also have genes for extracellular peptidases. All signal peptidases described so far are serine proteases. It is a family of subtilisin-like peptidases. The encoded proteins are members of the trypsin family of peptidases. E-64 is an epoxide which can irreversibly inhibit a wide range of cysteine peptidases. These can include&colon; surface adhesins, mannans, enzymes such as proteinases, peptidases, DNases, and lipases. This breaks down the multimers into smaller units, which are degraded by other peptidases. The protein encoded by this gene is a member of the trypsin family of peptidases. Enzymes, e.g. peptidases and artificial catalysts, are known to accelerate the hydrolysis reactions. They inhibit serine peptidases of the S1 family (INTERPRO). The presence and position of disulfide bridges are other conserved features of aspartic peptidases. Ricin is resistant, but not impervious, to digestion by peptidases. The families of peptidases are constructed by comparisons of amino acid sequences. Even though there are a few prokaryote kexin-like peptidases, all kexins are eukaryotes. Many, but not all, of these peptidases are zinc metalloenzymes.