Why do we only talk about Dglucose when discussing human met

Why do we only talk about D-glucose when discussing human metabolism?

What’s the major difference between amylose and amylopectin?

Which one contributes mostto the carbohydrate content of a potato, or carrot, or kernel of corn… or any starchy food?

What’s so great about the structure of glycogen?

Why is this such a big deal when we thinkabout the primary function of glycogen in both the muscle and liver?

What’s the primary carbohydrate digestive enzyme? How does it work? Where do our disaccharidases hang out?

Solution

Only D-glucose is naturally present in the nature and in animals. L-glucose is artificially synthesized. L-glucose cannot be phosphorylated by Hexokinase, the first enzyme of glucose metabolism, and hence it cannot proceed further in the glycolysis cycle.

Amylose is a straight chain polymer of D-glucose with alpha 1-4 glycosidic linkage

Amylopectin is a branched chain polymer of D-glucose with alpha 1-4 glycosidic linkage and alpha1-6 glycosidic linkage at branch points.

Potato has more carbohydrates compared to the other items mentioned.

Amylase is the primary carbohydrate digestive enzyme. Amylases are of 3 types. Alpha, Beta and Gamma amylases. Alpha amylase breaks long chain carbohydrates at random places. Beta amylase acts on the non reducing end of the long chain of carbohydrates and gamma amylase acts from the reducing end of the chain. Disaccharides reach the small intestine and are acted upon by the digestive enzymes.