3.4.23.23 Mucor pusillus gene expressed in Saccharomyces cerevisiae 3.4.23.23 in Escherichia coli 3.4.23.23 aspartic proteinase gene expressed in Pichia pastoris 3.4.23.23 expressed in Pichia pastoris 3.4.23.23 expressed in Pichia pastoris GS115 cells