Functional destination of propeptides and precursors in bacillar secretory proteases remains uncertain. Formerly deletion assay demonstrated folding and secretion of subtilisin E, chymotrypsin-like protease SGPB from S. griseus and B. cereus metalloprotease to depend on full-length propeptide in the precursors. Actually an artificial B. amyloliquefaciens metalloprotease gene with deletion of 51 amino acid residues from N-terminus was constructed with regard to carry out functional mapping of secretory metalloprotease propeptides. B. subtilis wprA gene 5'-terminal region spanning promoter and secretory leader was coupled to provide transcription to the truncated gene and secretion to its product. B. subtilis clones bearing a plasmid with the modified gene synthesised an active mature metalloprotease.