Modified creatinase

The present invention relates to mutant polypeptides having creatine amidino hydrolase activity, wherein the polypeptides remain thermally stable activity in the presence of agents that modify thiol groups. The invention also relates to methods for producing the mutant polypeptides; and to the use of a sensor comprising the mutant polypeptide for measuring creatinine in a physiological fluid sample. In addition, the present invention teaches how to use the mutant polypeptides to increase the lifetime of creatinine sensors, as well as methods of making the sensors. 本发明涉及具有肌酸脒基水解酶活性的突变多肽，其中所述多肽在改性硫醇基的试剂存在下保持热稳定活性。本发明还涉及用于产生该突变多肽的方法；并且涉及包含该突变多肽的传感器用于测量生理流体样本中肌酸酐的用途。另外，本发明教导如何使用突变多肽提高肌酸酐传感器的寿命，以及制备传感器的方法。