Amino-terminal heterogeneity ofE. coliTEM-β-lactamase secreted fromBacillus subtilis

Abstract
E.coli TEM-β-lactamase, secreted from Bacillus subtilis after transformation with three different hybrid plasmids, was purified and subjected to direct amino-terminal sequence analysis. The results show that the signal sequence cleavage site varies depending on the hybrid plasmid construction and cannot be exactly predicted from the DNA sequences. The results are of general interest if recombinant DNA technology is used to synthesize, e.g. pharmaceutical products where the preservation of the authentic amino-terminal structure is highly desirable.