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M20 Peptidase Xaa-His dipeptidase (PepV) degrades hydrophobic dipeptides Peptidase M20 family, Peptidase V (Xaa-His dipeptidase; PepV g.p. (Lactobacillus lactis); X-His dipeptidase; beta-Ala-His dipeptidase; carnosinase) subfamily. The PepV group of proteins is widely distributed in lactic acid bacteria. PepV, along with PepT, functions at the end of the proteolytic processing system. PepV is a monomeric metalloenzyme that preferentially degrades hydrophobic dipeptides. The Streptococcus gordonii PepV gene is homologous to the PepV gene family from Lactobacillus and Lactococcus spp. PepV recognizes and fixes the dipeptide backbone, while the side chains are not specifically probed and can vary, rendering it a nonspecific dipeptidase. It has been shown that Lactococcus lactis subspecies lactis (L9) PepV does not hydrolyze dipeptides containing Pro or D-amino acids at the C-terminus, while PepV from Lactobaccilus has been shown to have L-carnosine hydrolyzing activity. The mammalian PepV also acts on anserine and homocarnosine (but not on homoanserine), and to a lesser extent on some other aminoacyl-L-histidine dipeptides. Also included is the Staphylococcus aureus metallopeptidase, Sapep, a Mn(2+)-dependent dipeptidase where large interdomain movements could potentially regulate the activity of this enzyme.
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