endopeptidase or endoproteinase are proteolytic peptidases that break peptide bonds of nonterminal amino acids (i.e. within the molecule), in contrast to exopeptidases, which break peptide bonds from their end-pieces. for this reason, endopeptidases cannot break down peptides into monomers, while exopeptidases can break down proteins into monomers. a particular case of endopeptidase is the oligopeptidase, whose substrates are oligopeptides instead of proteins. they are usually very specific for certain amino acids. examples of endopeptidases include: * trypsin - cuts after arg or lys, unless followed by pro. very strict. works best at ph 8. * chymotrypsin - cuts after phe, trp, or tyr, unless followed by pro. cuts more slowly after his, met or leu. works best at ph 8. * elastase - cuts after ala, gly, ser, or val, unless followed by pro. * thermolysin - cuts before ile, met, phe, trp, tyr, or val, unless preceded by pro. sometimes cuts after ala, asp, his or thr. heat stable. * pepsin - cuts before leu, phe, trp or tyr, unless preceded by pro. also others, quite nonspecific; works best at ph 2. * glutamyl endopeptidase (alias glu-c) - cuts after glu. works best at ph 8. == references ==  == external links == *  == see also == * exopeptidase * the proteolysis map 
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