Reversible inactivation of phenylalanine hydroxylase by catecholamines in cultured hepatoma cells.
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چکیده
منابع مشابه
Reversible inactivation of phenylalanine hydroxylase by catecholamines in cultured hepatoma cells.
Phenylalanine hydroxylase in Reuber H4 hepatoma cell cultures can be rapidly inactivated by the addition of epinephrine, norepinephrine, dopamine, or 3,4-dihydroxyphenylalanine, in order of decreasing effectiveness, to the culture medium. The enzyme was 50% inactivated in 1 hour by 25 muM (R)-epinephrine or 45 muM (R)-norepinephrine in the medium. High concentrations of epinephrine caused a 70%...
متن کاملProperties of Phenylalanine Hydroxylase of Cultured Hepatoma
The kinetic and immunologic properties of phenylalanine hydroxylase of adult rat liver were compared to the properties of the similar enzyme present in cultured H4-II-E-C3 hepatoma cells. The enzymes from the two sources could not be distinguished by the K, values for either phenylalanine or 6,7-dimethyltetrahydropterin. Analysis by double immunodiffusion showed that phenylalanine hydroxylase f...
متن کاملProperties of phenylalanine hydroxylase of cultured hepatoma cells.
The kinetic and immunologic properties of phenylalanine hydroxylase of adult rat liver were compared to the properties of the similar enzyme present in cultured H4-II-E-C3 hepatoma cells. The enzymes from the two sources could not be distinguished by the Km values for either phenylalanine or 6,7-dimethyltetrahydropterin. Analysis by double immunodiffusion showed that phenylalanine hydroxylase f...
متن کاملMechanism of Inactivation of Phenylalanine Hydroxylase by p-Chlorophenylalanine in Hepatoma Cells in Culture
The mechanism by which p-chlorophenylalanine specifically reduces phenylalanine hydroxylase activity in rat liver in uiuo and in Reuber H4 hepatoma cells in culture has been investigated. Chromatography on hydroxylapatite of liver extract from rats injected with p-chlorophenylalanine showed that the compound differentially affected the three normal phenylalanine hydroxylase isoenzymes (I, II, a...
متن کاملEffect of serum on phenylalanine hydroxylase levels in cultured hepatoma cells.
Continued high levels of phenylalanine hydroxylase in cultured H4-II-E-C3 rat hepatoma cells require either serum or glucocorticoids in the culture medium. Upon withdrawal of serum, cellular phenylalanine hydroxylase levels decay exponentially with a half-life of 22 hours for about 60 hours, after which time a low, constant enzyme content persists for at least 96 hours. This decline of phenylal...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1976
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(17)33396-3