Extracellular secretion of pullulanase is unaffected by minor sequence changes but is usually prevented by adding reporter proteins to its N- or C-terminal end

Pullulanase secretion from Escherichia coli containing secretion genes from Klebsiella oxytoca was not inhibited by 23 separate linker insertions of 2-4 codons each, but was inhibited by fusion of reporter proteins to either the N- or C-terminus. Shortening one reporter protein, however, did permit secretion. Eleven of the insertions abolished pullulanase activity. The reporter hybrids did not alter activity, suggesting that pullulanase conformation was not significantly changed in these hybrids.