Tryptophan catabolism by tryptophan pyrrolase in rat liver. The effect of tryptophan loads and changes in tryptophan pyrrolase activity.

We investigated how changes in tryptophan pyrrolase activity and tryptophan loads affect the breakdown of tryptophan was estimated by injecting rats with [ring-2-14-C]tryptophan and measuring respiratory 14-CO2. We concluded, contrary to previous reports, that induction of tryptophan pyrrolase definitely will increase the rate of tryptophan breakdown. Tryptophan loads also increase tryptophan breakdown even in circumstances where there is no increase in tryptophan pyrrolase activity, presumably by increasing the saturation of the enzyme. After a tryptophan load (50 mg per kg) the increase in liver tryptophan concentration lasts only 30 min. The rapid return of liver tryptophan to normal may be due partly to the high turnover rate of liver tryptophan. We estimate that tryptophan pyrrolase degrades tryptophan in vivo at a rate that is equivalent to the whole liver tryptophan concentration in 7.5 min or less.

• Publication year

  1975

• Venue

  Journal of Biological Chemistry

• Publication date

  1975-07-10

• Fields of study

  Biology, Medicine

• Identifiers
  DOI 10.1016/s0021-9258(19)41270-2PMID 1150652
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

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