Cerebral Hydroxylases: Stimulation by a New Factor

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Science  23 Feb 1973:
Vol. 179, Issue 4075, pp. 809-811
DOI: 10.1126/science.179.4075.809


Cerebral tryptophan 5-hydroxylase and tyrosine hydroxylase are stimulated by a solution of lyophilized, protein-free 30,000g supernatant of brain homogenates (concentrate 1). This preparation can be further purified by passage through Sephadex G-75 and phosphocellulose columns to yield concentrate 2. Unlike concentrate 1, concentrate 2 is unstable after several days of storage even at -27°C. Neither preparation is active without the presence of a reduced pteridine cofactor. The stimulating factor appears to be thermostable, alkali-labile, dialyzable, and light-sensitive.