Abstract: Recombinant vectors and a method for producing a predetermined protein in a trademark microbial host are provided. The recombinant vectors are autonomously replicable expression vectors for use in B. subtilis and E. coli and express proteins therein. The vectors contain DNA sequences which code for preprolysostaphin protein secretion sequences which are necessary and sufficient for efficient secretion of the predetermined protein by transformed hosts. A gene for a predetermined protein is inserted into the vectors such that the order of genes in the vector is 5'-vector DNA-preprolysostaphin protein secretion sequence-predetermined protein sequence-vector DNA-3'. Optionally and preferably, the vectors also contain additional DNA sequences coding for staphylococcal nuclease which is a secretable detectable protein tag.