11426362001

Hexokinase (HK)

suspension, suitable for detection

• Sinónimos: HK, Hexokinase
• Comisión internacional de enzimas: 2.7.1.1 (BRENDA, IUBMB)
• Código UNSPSC: 12352204

Propiedades

• Formulario: suspension
• Nivel de calidad: 100
• actividad específica: ~450 units/mg protein (At 25 °C and pH 7.6 with D-glucose and ATP as the substrates.)
• envase: pkg of 1 mL (1,500 U)
• fabricante / nombre comercial: Roche
• intervalo de pH: 6.0-8.0
• aplicaciones: detection
• Condiciones de envío: wet ice
• temp. de almacenamiento: 2-8°C

Descripción

Descripción general

ATP:D-hexose 6-phosphotransferase

Hexokinase consists of 486 amino acids and has a molecular weight of 57,000 D (SDS-PAGE) in citrate/phosphate buffer. It may form dimers under other buffer conditions.

Hexokinase exists in three isozymes, namely type I, type II and type III that differ in subcellular localization, catalytic and regulatory properties. The type I isozyme serves a catabolic function facilitating the entry of glucose into glycolytic metabolism for energy production. The type II and type III enzymes perform anabolic functions, such as generating G6P for glycogen synthesis or metabolism through the phosphogluconate pathway for lipid synthesis. Type I and type II isozymes have been found to be bound to mitochondria. The type III isozyme has been found to have perinuclear localization in several cell types.[1]

Aplicación

Hexokinase (HK) has been used in enzyme assays[2][3] and chemiluminescence assay.[4] It has also been used to determine ATP concentration.[5]

Use Hexokinase for the determination of D-glucose[6][2], D-fructose, and D-sorbitol in food or biological research samples. Hexokinase may also be used for the assay of other saccharides, which are convertible to glucose or fructose, and is, therefore, useful in the assay of many glycosides.
Hexokinase has been used in the enzymatic detection of nitric oxide[4] and in the measurement of ATP by luminescence method.[7]

Acciones bioquímicas o fisiológicas

Hexokinase catalyzes the conversion of hexoses to hexose-6-phosphate in an ATP-dependent manner. It is also called as the glycolytic enzyme as it catalyzes the first step in glucose metabolism with the formation of glucose-6-phosphate (G6P). In eukaryotes, it functions as a glucose sensor.[8]

Calidad

Contaminants: <0.002% PGI, <0.0005% G6P-DH and GR, each, <0.001% CK, MK, 6-PGDH, and ADH, each, <0.05% GIDH and invertase (β-fructosidase), each, <30 μg/ml glucose (enzymatically)

Definición de unidad

Unit Assay: For measuring hexokinase activity 0.22 M glucose in 0.1 M triethanolamine buffer, pH 7.6, 6.5 mM MgCI₂, 2.7 mM ATP, 0.83 mM NADP is incubated in the presence of 1.7 U glucose-6-phosphate dehydrogenase with an appropriate amount of hexokinase (10–20 mU) at +25 °C (total volume: 3.0 ml). The enzyme activity is calculated from the increase of absorbance at 340 nm ( = 6.3 [I × mmol/l^-1 × cm-1]) or 365 nm ( = 3.5 [I × mmol/l^-1 × cm^-1]).

Forma física

Suspension in 3.2 M ammonium sulfate solution, pH approximately 6.5

Nota de preparación

Activator: Hexokinase requires Mg²⁺ ions (K_m = 2.6 mM) for activity. Catecholamines too increase activity.
Stabilizers: Thiols

Otras notas

For life science research only. Not for use in diagnostic procedures.

Información de seguridad

• Código de clase de almacenamiento: 12 - Non Combustible Liquids
• Clase de riesgo para el agua (WGK): WGK 1
• Punto de inflamabilidad (°F): does not flash
• Punto de inflamabilidad (°C): does not flash