Hexokinase 1 (HXK1) Human Recombinant Active Protein

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, the first step in most glucose metabolism pathways. This gene encodes a ubiquitous form of hexokinase which localizes to the outer membrane of mitochondria. Mutations in this gene have been associated with hemolytic anemia due to hexokinase deficiency. Alternative splicing of this gene results in five transcript variants which encode different isoforms, some of which are tissue-specific. Each isoform has a distinct N-terminus; the remainder of the protein is identical among all the isoforms. A sixth transcript variant has been described, but due to the presence of several stop codons, it is not thought to encode a protein. [provided by RefSeq, Apr 2009]

HK1: a glycolytic enzyme that catalyzes the reaction ATP + D-hexose = ADP + D-hexose 6-phosphate. The first and rate-limiting step in glycosis, a pathway that produces energy in the form of ATP from glucose. An allosteric enzyme inhibited by its product glucose-6-phosphate (Glc-6-P). HK-2 and its mitochondrial receptor (VDAC) play the most pivotal and direct roles in the ""Warburg effect"". Acts as a ""glucose sensor"" by trapping glucose inside the cell by catalyzing its phosphorylation to produce Glc-6-P. In vertebrates there are four major glucose-phosphorylating isoenzymes, designated hexokinase I, II, III and IV (glucokinase). Four human isoforms are produced by alternative splicing and alternative initiation. Isoform HK1 is markedly elevated in rapidly growing tumor cells exhibiting high glucose catabolic rates. HK1 is present in most tissues but is especially prominent in brain and kidney. Isoform HK1-SC is is an integral membrane protein detected in round spermatids, condensing spermatids and mature sperm where it is found in the head membranes, mitochondria of the midpiece and the fibrous sheath of the flagellum. Isoform HK1-SA is first expressed during meiosis and continues to be present in postmeiotic germ cells while isoform HK1-SB is present only in postmeiotic germ cells.

Protein type: Carbohydrate Metabolism - amino sugar and nucleotide sugar; Kinase, other; Mitochondrial; EC 2.7.1.1; Carbohydrate Metabolism - fructose and mannose; Carbohydrate Metabolism - starch and sucrose; Carbohydrate Metabolism - galactose; Carbohydrate Metabolism - glycolysis and gluconeogenesis

Chromosomal Location of Human Ortholog: 10q22

Cellular Component: mitochondrial outer membrane; mitochondrion; cytosol; lipid raft

Molecular Function: protein binding; hexokinase activity; mannokinase activity; fructokinase activity; glucokinase activity; ATP binding

Biological Process: hexose metabolic process; glycolysis; hexose transport; carbohydrate phosphorylation; glucose 6-phosphate metabolic process; carbohydrate metabolic process; cell glucose homeostasis; pathogenesis; glucose transport; transmembrane transport

Disease: Hemolytic Anemia, Nonspherocytic, Due To Hexokinase Deficiency; Neuropathy, Hereditary Motor And Sensory, Russe Type