Enzymatic studies of glucuronide formation in impaired liver. II. Activating effect of boiled liver extract on liver glucuronide formation

The effect of the boiled liver extract on the velocity of 4-methyl umbelliferone lucuronide formation by mouse liver homogenate was studied. The results were as follows: 1. Addition of mouse or rat liver boiled extract to the complete system for the glucuronide formation produced an increase in the velocity of the glucuronide formation. 2. The boiled liver extract produced the increase in the velocity of the glucuronide formation not as a substrate but as an activator. 3, The activator in the boiled liver extract was relatively heat stable, acid labile, and precipitated as a fairly ethanol-soluble barium salt. The solution of the activator partially purified by ethanol fractionation of the barium salt indicated its absorption maximum at 262 mμ. These results suggested that the most possible substance in the boiled liver extract responsible for the activation of 4methyl umbelliferone glucuronide formation might be a sugar nucleotide.