The loxP-flanked exon 2 of Serpina6tm1Mmp, containing the entire protein coding sequence, has been excised by Cre recombinase. Quantitative real-time PCR analysis of liver mRNA detects no transcripts from the targeted gene in homozygous mutant mice and ~50% of wild-type transcript levels in heterozygous mice. Immunoblot analysis of plasma of homozygous mutant, heterozygous and wild-type mice yields confirmatory results for the for the protein.