A-D-Glucose I-phosphate

Glucose derivatives. a-D-Glucose i-phosphate can be prepared by the action of potato phosphorylase on starch or synthesized from acetobromo glucose and trisilver phosphate or silver diphenyl phosphate . 

This enzyme [EC 2.4.1.1], also called phosphorylase, catalyzes the reaction of [(l,4)-o -D-glucosyl] with orthophosphate to produce [(l,4)-o -D-glucosyl] -i and a-D-glucose 1-phosphate. The name to be used with this enzyme is dependent on the naturally occurring substrate for example, glycogen phosphorylase, starch phosphorylase, maltodextrin phosphorylase, etc. 

A number of hexose phosphates have been isolated from natural sources. Of these oTructose 1,6-diphosphate (Harden-Young ester) (I), D-fructose 6-phosphate (Neuberg ester) (II), D-glucose 6-phosphate (Robison ester) (III), and a-D-glucose 1-phosphate (IV) are of particular biochemical importance in the processes of fermentation and glycolysis. These hexose phosphates are interconvertible in the presence of the proper enzymes and cofactors. 

This enzyme [EC 2.7.1.63], also known as polyphosphate-glucose phosphotransferase, catalyzes the reaction of [phosphatejn with o-glucose to yield [phosphate] ( i) and D-glucose 6-phosphate. The enzyme requires the presence of a neutral salt (such as potassium chloride) for maximum activity. Glucosamine can also serve as a substrate. 

Inositol is synthesized by the same route in all cells. D-Glucose-6-phosphate (d-G-6-P) is converted to L-mvo-inositol-1 -phosphate (l-I- 1 -P), which can also be termed D-myo-inositol-3-phosphate. The L-I-l-P is then hydrolyzed to myoinositol by a relatively specific phosphatase. As we will see, enzymes that do these reactions in bacteria and archaea can have quite different characteristics from the eukaryotic enzymes. 

Figure 3.92 Proposed biosynthetic pathway for the kedarcidin chromophore. (a) 1-Mycarose and kedarosamine from D-glucose-1-phosphate (b) (i )-2-aza-3-chloro-p-tyrosine from 2-aza-l-phenylalanine.

Acetamido-2-deoxyglucose i>-form 1,3,4-Tri-Ac, 6-phosphate, A-8 2-Acetamido-2-deoxy-a-D-glucose l-(dihydrogen phosphate). A-271... 

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