Glucokinase

Reaction 1 Phosphorylation of Glucose hy Hexokinase or Glucokinase—The First Priming Reaction... 

Liver contains an enzyme called glucokinase, which also carries out the reaction in Figure 19.4 but is highly specific for D-glucose, has a much higher for glucose (approximately 10.0 mAf), and is not product-inhibited. With such... 

Glucokinase Is Important in Regulating Blood Glucose After a Meal... 

Figure 19-5. Variation in glucose phosphorylating activity of hexokinase and glucokinase with increase of blood glucose concentration. The for glucose of hexokinase is 0.05 mmol/L and of glucokinase is 10 mmol/L.

The liver regulates the blood glucose after a meal because it contains the high-AJj glucokinase that promotes increased hepatic utilization of glucose. 

The uptake of glucose into the liver is independent of insulin, but liver has an isoenzyme of hexokinase (glucokinase) with a high K, so that as the concentration of glucose entering the liver increases, so does the... 

Figure 37-14. Alternative promoter use in the liver and pancreatic B cell glucokinase genes. Differential regulation of the glucokinase GK) gene is accomplished by the use of tissue-specific promoters. The B cell GK gene promoter and exon 1B are located about 30 kbp upstream from the liver promoter and exon 1L. Each promoter has a unique structure and is regulated differently. Exons 2-10 are identical in the two genes, and the GK proteins encoded by the liver and B cell mRNAs have identical kinetic properties.

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