title: Tyrosinase-mediated inhibition of in vitro leucine incorporation into mouse melanoma by 4-isopropylcatechol.
abstract: The effect of 4-isopropylcatechol (4-IPC), a potent, irreversible cutaneous depigmenting agent, on protein biosynthesis of malignant melanoma cells in mice was studied by examining the in vitro amino acid (leucine) incorporation into a microsome fraction in cell sap. The present study revealed that 4-IPC does not inhibit the protein biosynthesis of the cell-free system in mouse liver, but remarkably inhibits it in mouse melanoma cells, which contain a high level of tyrosinase. The enhanced inhibition was found also in the mouse liver cell-free system when tyrosinase was added. Air oxidation products of 4-IPC were not responsible for such inhibition. These results may indicate that 4-IPC directly inhibits protein biosynthesis, probably by some intermediates that occur in an early stage of enzymatic oxidation of 4-IPC.
mesh_terms: D000818:Animals; D004156:Catechol Oxidase / Q000494:pharmacology*; D002396:Catechols / Q000494:pharmacology*; D002474:Cell-Free System / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects; D066298:In Vitro Techniques; D007930:Leucine / Q000378:metabolism; D008297:Male; D008544:Melanocytes / Q000187:drug effects; D008545:Melanoma / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D009374:Neoplasms, Experimental / Q000201:enzymology / Q000378:metabolism; D010084:Oxidation-Reduction; D014176:Protein Biosynthesis
chemical_list: D002396:Catechols; D004156:Catechol Oxidase; D007930:Leucine