|
As an attempt to clarify one end of the metabolic fate of purine bases in rat calvaria and liver, the activities of xanthine oxidase and guanine aminohydrolase were assayed. The portions of calvarias containing frontal and parietal bones, and liver were separated from rats weighing 20010 gm. Specimens were assayed for their activities of xanthine oxidase and guanine aminohydrolase in its cytosol. Specific activities of xanthine oxidase with hypoxanthine or xanthine as substrate, and guanine aminohydrolase in liver were 3.99 or 7.48, 11.40 mu/mg of protein, respectively. Xanthine oxidase and guanine aminohydrolase in calvaria, however, had significantly lower than liver. The results suggested that the salvage pathway might be active in rat calvaria, showing that purine metabolism in the tissue seemed to be regulated economically. The results also showed that catabolic fate of purine bases varied from tissue to tissue within the same species.
|