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 3.4.23.23 in Escherichia coli 3.4.23.23 Mucor pusillus gene expressed in Saccharomyces cerevisiae