Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:1.10.3.1 (
tyrosinase
)
9,065
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The effect of estrogens on
tyrosinase
(EC 1.14.18.1) activity was studied in B16/C3 melanoma cultures. Estradiol, estriol, and other related steroids failed to influence
tyrosinase
activity when added to the medium of proliferating cultures. Imidazole (10 mM), on the other hand, induced the activity of that enzyme 3-fold, as reported previously. Estradiol and estriol blocked imidazole induction, however, unlike the other estrogenic compounds. The blockade occurred within 15 min of hormone addition and was reversible. Dose-response studies revealed that the maximal estradiol effect occurred at 0.75 nM and the half-maximal effect occurred at 0.5 nM.
Estriol
was more potent, with the maximal blockade occurring at approximately 0.5 nM and half-maximal effect at 0.25 nM. The induction of
tyrosinase
by imidazole and the blockade of this induction by estradiol and estriol could not be demonstrated in broken cell preparations, suggesting that direct enzyme activation-inactivation was not involved. Studies utilizing inhibitors of protein and RNA synthesis suggest that this effect is mediated at a pre-translational level and is independent of mRNA destabilization.
...
PMID:Inhibition of imidazole-induced tyrosinase activity by estradiol and estriol in cultured B16/C3 melanoma cells. 312 3
