Alterations in the cleavage site of the signal sequence for the secretion of human lysozyme by Saccharomyces cerevisiae

The amino acids corresponding to the cleavage site of a hybrid preprotein containing a chicken lysozyme signal and a mature portion of human lysozyme were altered. The processing of mutant signals of -3Pro and -3Asp/-1Ala decreased remarkably, while that of -2Pro was 75% of that of the native signal. The major cleavage site of -3Pro was the same as that of the native signal, but that of the -2Pro and -3Asp/-1Ala signals was shifted one residue closer to the N-terminal side than the original site. The cleavage of the -2Pro signal, which was identical to the native processing of pheasant prelysozyme, suggested that the signal peptidases in yeast and bird are similar.