A PGK-neomycin resistance cassette replaced half of exon 8 and all of exon 9, sequences that encode zinc and substrate binding sites. RT-PCR analysis using primers that span the entire coding region detected a truncated transcript in liver from homozygous mutant mice. Western blot analysis using polyclonal antibodies raised against a peptide encoded by exon 5 did not detect protein in plasma from homozygous mutant mice. (J:73713)