Abstract: A stabilized liquid enzyme composition is prepared containing at least one enzyme substrate or analog thereof and/or at least one enzyme product or analog thereof combined with the enzyme in a liquid medium containing. The liquid medium may be human, animal or artificial serum. The composition may also contain an activator chosen from a sulfhydryl compound and a divalent metal ion. In a preferred embodiment, the enzyme is isolated creatine kinase MB(CKMB), the substrate may be adenosine triphosphate, its oxidized or analog form, creatine or its analog, and the product may be adenosine diphosphate, its oxidized or analog form or phosphocreatine or its analog. The activator is preferably N-acetyl-cysteine or .beta.-mercaptoethanol. In a preferred embodiment, CKMB is stabilized with a combination of adenosine triphosphate and creatine. A preferred serum is heat-inactivated alkaline-shocked human serum.

Abstract: The present invention relates to the measurement of glycated hemoglobin by fluorescence quenching. The present invention uniquely involves performing two sequential fluorescent quenching measurements: one measurement of the fluorescent quenching due to total hemoglobin in the sample and a second measurement of the fluorescent quenching due to glycated hemoglobin present in the sample after the non-glycated hemoglobin is removed. Glycated hemoglobin and non-glycated hemoglobin can be separated by a variety of methods as described herein, including ion capture and phase separations.