The present invention relates to two novel, testis-specific proteins (C19 and C23) that arc lysozyme paralogues. The proteins are believed to play a role in capacitation of sperm and the fertilization of the ovum. Therefore these compounds make ideal targets for the design of contraceptive agents. The C19 and C23 proteins can also be modified to establish lysozyme activity and the modified proteins can then be used in all applications that currently exist for lysozymes.