Disclosed is a method of expressing enzymatically-active, recombinant proteolytic tryptase in a eukaryotic host cell, expression constructs which drive the production of enzymatically-active tryptase in transformed hosts, and genetically-engineered eukaryotic host cells containing the expression constructs and which express enzymatically-active proteolytic tryptases. Uses for the proteolytic tryptases so produced are also disclosed. Also disclosed is a method of making active site mutants of proteolytic tryptases in a eukaryotic host cell, expression constructs which drive the production of the mutants in transformed eukaryotic host cells, and genetically-engineered eukaryotic host cells containing the expression constructs and which express the active-site mutated form of proteolytic tryptases.