Glucokinase (GCK) Recombinant Protein

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, the first step in most glucose metabolism pathways. Alternative splicing of this gene results in three tissue-specific forms of glucokinase, one found in pancreatic islet beta cells and two found in liver. The protein localizes to the outer membrane of mitochondria. In contrast to other forms of hexokinase, this enzyme is not inhibited by its product glucose-6-phosphate but remains active while glucose is abundant. Mutations in this gene have been associated with non-insulin dependent diabetes mellitus (NIDDM), maturity onset diabetes of the young, type 2 (MODY2) and persistent hyperinsulinemic hypoglycemia of infancy (PHHI). [provided by RefSeq, Apr 2009]

GK: a glycolytic enzyme that catalyzes glucose metabolism in the liver and pancreatic beta cells. Acts as a ""glucose sensor"" in beta cells. The first and rate-limiting step in glycosis, a pathway that produces energy in the form of ATP from glucose. Glucokinase traps glucose inside the cell by catalyzing its phosphorylation to produce glucose-6-phosphate. Has a lower affinity for glucose than the three other isozymes of hexokinase, allowing other organs such as the brain and muscles to have first call on glucose when its supply is limited. Unlike other hexokinases, glucokinase is not inhibited by glucose-6-phosphate. Glucokinase is found in the outer membrane compartment of mitochondria. May bind VDAC, suppressing mitochondrial function. Glucokinase transcription is induced by insulin, perhaps via the activation of Stat 5B. Mutant glucokinase causes a rare form of diabetes and may also play a role in type 2 diabetes. Three splice variant isoforms of human glucokinase have been described.

Protein type: Carbohydrate Metabolism - galactose; Carbohydrate Metabolism - glycolysis and gluconeogenesis; Kinase, other; Mitochondrial; Carbohydrate Metabolism - amino sugar and nucleotide sugar; EC 2.7.1.2; Carbohydrate Metabolism - starch and sucrose

Chromosomal Location of Human Ortholog: 7p15.3-p15.1

Cellular Component: nucleoplasm; mitochondrion; actin filament; cytosol; basal cortex; secretory granule

Molecular Function: protein binding; mannokinase activity; fructokinase activity; magnesium ion binding; glucokinase activity; ADP binding; protein phosphatase binding; ATP binding; glucose binding

Biological Process: glucose 6-phosphate metabolic process; positive regulation of glycogen biosynthetic process; lipid homeostasis; pathogenesis; glucose transport; glucose homeostasis; NADP metabolic process; cellular response to glucose starvation; detection of glucose; elevation of cytosolic calcium ion concentration; negative regulation of gluconeogenesis; regulation of glycolysis; transmembrane transport; second-messenger-mediated signaling; glycogen biosynthetic process; glycolysis; regulation of potassium ion transport; glucose metabolic process; positive regulation of insulin secretion; endocrine pancreas development; fructose 2,6-bisphosphate metabolic process; cellular response to insulin stimulus; hexose transport; carbohydrate metabolic process; positive regulation of glycolysis; carbohydrate phosphorylation; negative regulation of epinephrine secretion; cell glucose homeostasis; regulation of insulin secretion; positive regulation of phosphorylation

Disease: Hyperinsulinemic Hypoglycemia, Familial, 3; Diabetes Mellitus, Permanent Neonatal; Maturity-onset Diabetes Of The Young, Type 2; Diabetes Mellitus, Noninsulin-dependent