Overview:

Hexokinases phosphorylate hexoses to form hexose phosphate (1). The preferred substrate of these ubiquitous enzymes is D-glucose, but they can also phosphorylate other hexoses to varying degrees (2). Hexokinase is used in diagnostic tests to estimate the plasma glucose concentration of serum or plasma samples (3). In the hexokinase method of plasma glucose estimation, glucose in the sample first reacts with adenosine triphosphate (ATP) with the help of the hexokinase enzyme to form glucose-6-phosphate. Glucose-6-phosphate is then acted upon by glucose-6-phosphate dehydrogenase (G6PD) in the presence of NADP+ or NAD+ to form NADPH or NADH and 6-phosphogluconate. The amount of NADPH or NADH generated is measured by recording absorbance at 340 nm, which is proportional to the glucose concentration in the sample.

References:

1. Ciscato F, Ferrone L, Masgras I, Laquatra C, Rasola A. Hexokinase 2 in Cancer: A Prima Donna Playing Multiple Characters. Int J Mol Sci. 2021 Apr 29;22(9):4716. PMID: 33946854; PMCID: PMC8125560.

2. Cárdenas ML, Cornish-Bowden A, Ureta T. Evolution and regulatory role of the hexokinases. Biochim Biophys Acta. 1998 Mar 5;1401(3):242-64. PMID: 9540816.

3. Ambade VN, Sharma YV, Somani BL. METHODS FOR ESTIMATION OF BLOOD GLUCOSE : A COMPARATIVE EVALUATION. Med J Armed Forces India. 1998 Apr;54(2):131-133.