Aspartic proteases which the proteases that operate in acidic solutions have the same catalytic domain. This is why aspartic proteases typically work in specific places in different organisms, and are less prevalent than other proteases groups like serine proteases. Aspartic proteases’ sources vary, including stomach (pepsin gastricsin, pepsin and chymosin) as well as Lysosomes (cathepsins both E and D) and kidney (renin) and yeast granules and the fungi (secreted proteases e.g. penicillopepsin, rhizopuspepsin and endothiapepsin).