Abstract: Test strips by which creatine kinase activity can be quantitatively measured at a high sensitivity within a broad measuring range and which have excellent storage stability. Particularly, test strips for the measurement of creatine kinase activity, which comprises a carrier, a dehydrogenase, a diaphorase, NAD or NADP, and a water-soluble tetrazolium compound.

Abstract: A test strip which comprises a carrier, a dehydrogenase, diaphorase, a fluorescent chromogen, and NAD or NADP. The test strip provides high sensitivity and high accuracy measurement, and have excellent storage stability.

Abstract: The present invention relates to a reagent for measurement of magnesium ions utilizing a complex of magnesium ion with adenosine 5'-triphosphate as a substrate of glucokinase derived from bacteria of the genus Zymomonas. By using this reagent, enough measuring range to measure a magnesium ion in various samples such as biological fluids, foodstuffs, etc. can be accomplished and, at the same time, the measurement can be made with high precision and reliability even in a sample containing a magnesium ion in low concentration. Further, the reagent of the present invention is superior in operation property by reducing a dilution operation, and has sufficient performance for a routine method for determination of magnesium ions.