Glucosiduronic phenyl

IC with bovine enzyme which is very similar to the human one. Inhibitor concentration for 50% inhibition. K of substrate (phenyl a-D-mannopyranoside). K of substrate (4-nitrophenyl a-D-manno-pyranoside). K of substrate (4-nitrophenyl D-glucosiduronic acid). K of substrate (4-nitrophenyl 2-acetamido-2-deoxy- o-glueoside). Inhibitors were chitotetraono-1,5-lactone and chitotetraose, respectively. 

Garton, Robinson and Williams66 have studied the rate of acid hydrolysis of phenyl D-glucosiduronic acid as compared with phenyl acid sulfate. The ester acid sulfate was hydrolyzed completely by N hydrochloric acid at 93-95° in 10 minutes, 50 times as rapidly as the D-glucosiduronic acid. After 20 minutes, only 40% of the latter was hydrolyzed. On refluxing... 

The possibility that a D-glucuronic acid phosphate is an intermediate in the conjugation mechanism has been visualized, but no evidence has yet been found as to its participation. Touster and Reynolds22 have added /3-D-glueuronic acid 1-phosphate and lactate to mouse liver slices, and have found that it neither stimulates nor inhibits synthesis of o-amino-phenyl D-glucosiduronic acid. The problem needs further study, with radioisotopes. 

In 1951, Dutton and Storey reported that the synthesis of o-amino-phenyl 3-D-glucosiduronic acid requires the presence of boiled liver-extract. They subsequently identified the active principle of the boiled extract as uridine 5-(D-glucopyranosyluronic acid pyrophosphate). This discovery was the first reported instance of transglycosylation from a glycosyl nucleotide. 

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