The binding of pyridoxal 5-phosphate to aspartate aminotransferase of pig heart.
نویسندگان
چکیده
1. Oestrone 3-glucuronide has been identified as the reaction product after incubation of oestrone with a rabbit-liver microsomal preparation, uridine diphosphate glucuronic acid being used as the glucuronic acid donor. The formation of this compound was studied under various experimental conditions. 2. The reaction showed a maximum at pH 8.08-2, and Km for oestrone was found to be 9-7 x 10-5M. 3. The results are discussed in relation to the general problem of the physiological production of oestrogen glucuronides.
منابع مشابه
The unfolding and refolding of cytoplasmic aspartate aminotransferase from pig heart.
The unfolding of cytoplasmic aspartate aminotransferase from pig heart in solutions of guanidinium chloride (GdnHCl) was studied. Data from protein fluorescence, c.d. and thiol-group reactivity indicated that the enzyme was unfolded in 6 M-GdnHCl. Spectroscopic studies showed that this unfolding was accompanied by dissociation of the pyridoxal 5'-phosphate cofactor. On dilution of the GdnHCl, r...
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1. The a and ,B subforms of aspartate aminotransferase were purified from pig heart. 2. The a subform contained 2mol of pyridoxal 5'-phosphate. The apo-(a subform) could be fully reactived by combination with 2mol of cofactor. 3. The protein fluorescence of the apo(a subform) decreased non-linearly with increase in enzyme activity and concentration of bound cofactor. 4. It is concluded that the...
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The enzyme mitochondrial aspartate aminotransferase from beef liver is a dimer of identical subunits. The enzymatic activity of the resolved enzyme is restored upon addition of the cofactor pyridoxal 5-phosphate. The binding of 1 molecule of cofactor restores 50% of the original enzymatic activity, whereas the binding of a 2nd molecule of cofactor brings about more than 95% recovery of the cata...
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The concentrations of pyridoxal 5'-phosphate, and the holoenzyme activities and apoenzyme contents of alanine aminotransferase and aspartate aminotransferase in plasma were determined simultaneously in healthy individuals, patients with renal insufficiency with and without chronic haemodialysis and in patients with acute myocardial infarction. Plasma pyridoxal 5'-phosphate is significantly dimi...
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ورودعنوان ژورنال:
- The Biochemical journal
دوره 88 شماره
صفحات -
تاریخ انتشار 1963