| 摘要 |
The method for measuring the potassium concentration in a biological fluid, such as blood serum or whole blood, is carried out by fixing the amounts of phosphoenolpyruvate (PEP), adenosine diphosphate (ADP), pyruvate kinase and magnesium in the presence of a buffer in the enzymatic reaction I: <IMAGE> and measuring the rate of appearance of the products so that the reaction rate of pyruvate kinase can be determined. The reaction rate of this enzyme is directly proportional to the potassium content. The potassium concentration in the biological fluid which is to be checked is determined quantitatively by comparing the reaction rate of pyruvate kinase with a standard of known potassium concentration. The reaction rate of pyruvate kinase is preferably measured by determining the amount of pyruvate formed in reaction I by comparing the optical density of the resulting colour of the coupled reaction II and III: <IMAGE> where Pi is an inorganic phosphate and In is a colorimetric indicator with at least one colorimetric standard of known potassium concentration. A paper phase method for determining potassium contents in biological fluids is likewise presented.
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