Mouse cathepsin M, a placenta-specific lysosomal cysteine protease relatedto cathepsins L and P

The complete nucleotide sequence of a novel cathepsin cDNA derived from mou se placenta was determined and is termed cathepsin M. The predicted protein of 333 amino acid is a member of the family C1A proteases and is related t o mouse cathepsins L and P. Mouse cathepsin M is highly expressed in placen ta, whereas no detectable levels were found in lung, spleen, heart, brain, kidney, thymus, testicle, liver, or embryo. Phylogenic analyses of the sequ ences of human and mouse cathepsins show that cathepsin M is most closely r elated to cathepsins P and L. However, the differences are sufficiently lar ge to indicate that the enzymes will be found in other species. This is in contrast to human cathepsins L and V, which probably resulted from a gene d uplication after divergence of mammalian species. (C) 2000 Elsevier Science B.V. All rights reserved.