THAUMATIN WAS PURCHASED FROM SIGMA-ALDRICH (CATALOG # T7638) AND CONTAINED A MIXTURE OF THAUMATIN I ...THAUMATIN WAS PURCHASED FROM SIGMA-ALDRICH (CATALOG # T7638) AND CONTAINED A MIXTURE OF THAUMATIN I AND THAUMATIN II. LYS46 WAS USED IN PLACE OF ASN46 AND ASP113 WAS USED IN PLACE OF ASN113 AS WAS DONE IN ENTRY 1RQW AND AS SUGGESTED BY KO ET AL., ACTA CRYST. D50,813(1994).