Action of Ketene on Gonadotropic Hormones*
نویسندگان
چکیده
Ketene has been found to be a highly specific,acetylating agent for aqueous solution of proteins. It reacts only with amino, thiol, and phenolic hydroxy groups (1). Several investigators (24) have shown that the primary amino groups react most rapidly, while the hydroxy groups of tyrosine are acetylated at a much slower rate. The hydroxy groups in carbohydrate radicals of the protein molecule do not react, however, with ketene.l Ketene, therefore, should be particularly useful2 in determining whether the amino groups or the phenolic hydroxyls are essential for the biological activity of the sugar-rich proteins. Gonadotropic hormones obtained from the pituitary, and from pregnant mare serum and urine of pregnant women have been shown to be sugar-rich proteins (7). Since the carbohydrate groups do not react with ketene, and since thiol groups have not been found in these substances,3 any change found in the physiological activity of gonadotropic hormones after treatment with
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