Sandbox 172: Difference between revisions
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{{STRUCTURE_1cza| PDB=1cza | SCENE=Sandbox_172/Mynewscene/1 }} | {{STRUCTURE_1cza| PDB=1cza | SCENE=Sandbox_172/Mynewscene/1 }} | ||
==Hexokinase Type I== | ==Hexokinase Type I== | ||
Hexokinase Type I is one of four [http://en.wikipedia.org/wiki/Hexokinase hexokinase] isoenzymes that participate in [http://en.wikipedia.org/wiki/Glycolysis glycolysis]. Hexokinase catalyzes the phosphorylation of [http://en.wikipedia.org/wiki/glucose glucose] into [http://en.wikipedia.org/wiki/Glucose_6-phosphate glucose-6-phosphate] (G6P) providing enough activation energy for the glycolytic process to start. Thus hexokinase allows the muscle cells to take up glucose in the blood and use it as an energy source for different actions and expenditures. Hexokinase Type I is mainly found in mammalian tissues; it is crucial enzyme in maintaining a downward concentration gradient to provide a steady influx of glucose into cells. | Hexokinase Type I is one of four [http://en.wikipedia.org/wiki/Hexokinase hexokinase] isoenzymes that participate in [http://en.wikipedia.org/wiki/Glycolysis glycolysis]. Hexokinase catalyzes the phosphorylation of [http://en.wikipedia.org/wiki/glucose glucose] into [http://en.wikipedia.org/wiki/Glucose_6-phosphate glucose-6-phosphate] (G6P) providing enough activation energy for the glycolytic process to start. Thus hexokinase allows the muscle cells to take up glucose in the blood and use it as an energy source for different actions and expenditures. Hexokinase Type I is considered an enzyme of maintenence; it is unaffected by most physiological, metabolic and hormonal changes within the biological system. Hexokinase Type I is mainly found in mammalian tissues; it is crucial enzyme in maintaining a downward concentration gradient to provide a steady influx of glucose into cells. | ||
==Introduction== | ==Introduction== | ||
Four types of hexokinase isozymes exist in the human biological system. They all serve to catalyze the exact same reaction in glycolysis even though they are encoded by different sets of genes. The hexokinase types I-III all have a high affinity for glucose and become subject to inhibition in the presence of glucose-6-phosphate- the first step reaction product in glycolysis. Hexokinase type I is the predominant form in the muscle while hexokinase type II is the predominant form in myocytes. Hexokinase type IV varies from the other three hexokinase types as it is not inhibited by the production of glucose-6-phosphate and shows a lower affinity for glucose. Hexokinase type I and II have the particular ability to bind to outer mitochondrial membrane, this binding happens both specifically and reversibly.<ref name="one">Garavito R., Mulichuk A., Padmanabhan K., Wilson J. The structure of mammalian hexokinase-1. Nature Structural and Molecular Biology. 1998. '''5''': 555-560.</ref> | Four types of hexokinase isozymes exist in the human biological system. They all serve to catalyze the exact same reaction in glycolysis even though they are encoded by different sets of genes. The hexokinase types I-III all have a high affinity for glucose and become subject to inhibition in the presence of glucose-6-phosphate- the first step reaction product in glycolysis. Hexokinase type I is the predominant form in the muscle while hexokinase type II is the predominant form in myocytes. Hexokinase type IV varies from the other three hexokinase types as it is not inhibited by the production of glucose-6-phosphate and shows a lower affinity for glucose. Hexokinase type I and II have the particular ability to bind to outer mitochondrial membrane, this binding happens both specifically and reversibly.<ref name="one">Garavito R., Mulichuk A., Padmanabhan K., Wilson J. The structure of mammalian hexokinase-1. Nature Structural and Molecular Biology. 1998. '''5''': 555-560.</ref> | ||
