| 摘要 |
Mammalian pituitary growth hormone is modified by treatment in aqueous solution with 2.5 to 10 parts by weight of cyanogen bromide at a pH of 1 to 3 and a temperature of 20 DEG to 30 DEG C. for 1/2 to 16 hours, after which the modified hormone is recovered from the reaction mixture. The completion of the reaction may be shown by estimation of increase in N-terminal amino-acid content, and of decrease in the ratio of methionine residues to homoserine lactone residues. The product may be recovered by removal of cyanogen bromide and acid added to adjust the pH, by absorption of the mixture on a cross-linked dextran gel column followed by elution of the product, preferably together with dialysis of the solution, and then subsequent freeze drying or direct lyophilisation of the solution. The product is thus isolated as an amorphous powder. Examples are given for the preparation of modified human and bovine growth hormones. |
