The invention provides isolated nucleic acid molecules, designated COE-2 nucleic acid molecules, which encode novel carboxylesterase family members. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing COE-2 nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a COE-2 gene has been introduced or disrupted. The invention still further provides isolated COE-2 proteins, fusion proteins, antigenic peptides and anti-COE-2 antibodies. Diagnostic and therapeutic methods utilizing compositions of the invention are also provided.