The activity of tyrosine 3-monooxygenase is usually suppressed by an endogenous factor in brain.
Tyrosine 3-monooxygenase activity of the crude extract from rat striatum had a sharp pH optimum at pH 5.6 and showed almost no activity at pH 7 and higher. When the crude extract was adjusted to pH 5.2, the resulting precipitate showed high activity in the pH range of 6 to 7.5. Incubation of the acid-precipitated fraction with the acid-soluble fraction resulted in a remarkable decrease in the enzyme activity, as assayed at a neutral pH. These findings suggest that there is an endogenous factor inhibiting the activity of tyrosine 3-monooxygenase in rat brain.
D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D003342:Corpus Striatum / Q000201:enzymology* / Q000502:physiology; D000939:Epitopes / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors*
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000939:Epitopes; D014446:Tyrosine 3-Monooxygenase