CREATININE IMINOHYDROLASE FREE FROM UREASE ACTIVITY, METHODS OF PREPARATION AND USE, AND ASSAY COMPOSITIONS AND ANALYTICAL ELEMENTS CONTAINING SAME

摘要

A urease-free creatinine iminohydrolase enzyme preparation obtained from an aerobic soil microorganism. The enzyme of the preparation preferably has a molecular weight of from about 250,000 to 300,000; a maximum activity at a pH between 7 and 8 as measured at 37 DEG C.; a Km of about 3 to 5 mM for creatinine as measured at 37 DEG C., pH 7.5; and a specific activity for creatinine of at least about 1.0 unit per milligram of protein in the preparation as measured at 37 DEG C., pH 7.5. The preferred enzyme preparation is derived from the aerobic soil microorganism ATCC 31,546. Assay methods, compositions, and elements containing the aforementioned urease-free creatinine iminohydrolase for the determination of creatinine in an aqueous liquid are also disclosed.