Feeder's Pathway for Glycolysis.

Hello everyone.

I am sorry to neglect my blog for soooooo many days. But now that I am here, let's not waste time and take a look on my favorite Glycolysis pathway. For some reason, I always feel connected to EMP pathway more than other pathways. I have been loving it since my birth.

Man, seriously? O_O

Nah, actually I meant since my birth as a microbiologist :p

Off topic.

Back to the subject.

So we all are familiar with glycolysis and we know that it converts glucose into pyruvate, generates 4 ATP but utilises 2 of them, it has two phases, etc etc.

But today we will be talking about the feeder's pathway, which simply means the pathway for entry of other sugars except glucose. Today we will limit the discussion only to starch and glycogen.

Alright. Let's go.

First let's know an enzyme - glycogen phosphorylase (starch phosphorylase in plants).

This enzyme with a help of an inorganic phosphate attacks the (alpha 1-4 ) glycosidic linkage of the last glucose residue in the polymer and generates a glucose-1-phospahte. . Glycogen phosphorylase (or starch phosphorylase) acts repetitively until it approaches an ( alpha 1-6) branch point, where its action stops. A debranching enzyme removes the branches and once again glycogen or starch phosphorylase starts it's action.

Now the next step:

Glucose 1-phosphate produced by glycogen phosphorylase is converted to glucose 6-phosphate by

phosphoglucomutase, which catalyzes the reversible reaction

Glucose 1-phosphate - glucose 6-phosphate.

The glucose 6-phosphate thus formed can enter glycolysis or another pathway such as the pentose phosphate pathway, Thus hydrolysis of dietary polysaccharides and disaccharides into monosaccharides is important step for entering in the cells. 

Disaccharides must also be hydrolyzed to monosaccharides before entering cells.The monosaccharides so formed are actively transported into the epithelial cells , then passed into the blood to be carried to various tissues, where they are phosphorylated and funneled into the glycolytic sequence. 

A variety of D-hexoses, including fructose, galactose, and mannose, can be funneled into glycolysis. Each is phosphorylated and

converted to either glucose 6-phosphate or fructose 6-phosphate.

Here's an image I made to show the routes by which different sugars enter the preparatory phase of glycolysis.

Lots of love and high six.

Sorry to keep you waiting.

-Staph :D