Carbohydrate metabolism enzyme control

Weber, G., Lea, M. A., and Stamm, N. B., 1968, Sequential feedback inhibition and regulation of liver carbohydrate metabolism through control of enzyme activity, Adv. Enzyme Regul. 6 101. 

Magnesium plays an important role in the transmission of nerve impulses. It is also important in the activity of many enzyme reactions, for example carbohydrate metabolism. Magnesium sulfate is used as replacement therapy in hypomagnesemia Magnesium sulfate (MgS04) is used in die prevention and control of seizures in obstetric patients with pregnancy-induced hypertension (PIH, also referred to as eclampsia and preeclampsia). It may also be added to TPN mixtures. 

Biochemistry resulted from the early elucidation of the pathway of enzymatic conversion of glucose to ethanol by yeasts and its relation to carbohydrate metabolism in animals. The word enzyme means "in yeast," and the earlier word ferment has an obvious connection. Partly because of the importance of wine and related products and partly because yeasts are relatively easily studied, yeasts and fermentation were important in early scientific development and still figure widely in studies of biochemical mechanisms, genetic control, cell characteristics, etc. Fermentation yeast was the first eukaryote to have its genome elucidated. 

Morphological changes were also observed on callus of Pinus laricio cultured for 4 weeks with HS extracted from forest soil under Abies alba and Fagus sylvatica plantation or the hormones 2,4D, IAA, and 6BAP (Muscolo et al., 2005).The results showed that both high- and low-molecular-weight humic fractions inhibited callus growth compared to the control and affected the enzymes involved in carbohydrate metabolism. 

Figure 4. Coordinated control by reversible protein phosphorylation over the enzymes of carbohydrate metabolism in mammalian liver.

How does control of key enzymes control carbohydrate metabolism ... 

A number of control mechanisms operate in carbohydrate metabolism. They include allosteric effects, covalent modification, substrate cycles, and genetic control. These mechanisms affect key enzymes in different ways with different time responses. 

How does control of key enzymes control carbohydrate metabolism Glycogen synthase and glycogen phosphorylase are reciprocally controlled by phosphoryla-... 

Now that we know something about the effects of hormones in triggering responses within the cell, we can return to and expand on some earlier points about metabolic control. In Section 18.3, we discussed some points about control mechanisms in carbohydrate metabolism. We saw at that time how glycolysis and gluconeogenesis can be regulated and how glycogen synthesis and breakdown can respond to the body s needs. Phosphorylation and dephosphorylation of the appropriate enzymes played a large role there, and that whole scheme is subject to hormonal action. 

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