The goal of the review is description of the main characteristics of creatinine deiminase (CDI), an important bioanalytical tool for creatinine (Crn) assay. Crn is an essential metabolite for diagnostics of kidney disfunction and some other diseases, a biomarker to control the hemodialysis procedure, as well as an important analyte for sport medicine (estimation of general physiological status of athletes). We have described the important sources for CDI isolation, cloning of the corresponding gene, the construction of microbial recombinant strains, overproducing CDI, and characteristics of the enzyme from different microorganisms. There are reviewing also the new bioanalytical methods for quantitative determination of Crn, including enzymatic ones based on using CDI.
