The invention provides isolated nucleic acids molecules, designated 53010 nucleic acid molecules, which encode novel carboxylesterase members. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing 53010 nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a 53010 gene has been introduced or disrupted. The invention still further provides isolated 53010 proteins, fusion proteins, antigenic peptides and anti-53010 antibodies. Diagnostic methods utilizing compositions of the invention are also provided.