Sakai T, Perry J W, Hori C, Oka T
Biochim Biophys Acta. 1980 Aug 7;614(2):577-82. doi: 10.1016/0005-2744(80)90246-6.
The activity of S-adenosyl-L-methionine decarboxylase (S-adenosyl-L-methionine carboxy-lyase, EC 4.1.1.50) purified from mouse mammary gland can be stimulated by physiological concentrations of putrescine (Ka = 5 x 10(-7) M). In contrast, the elevation of the intracellular concentrations of putrescine in cultured mouse mammary tissue by exogenous addition of putrescine or by cultivation of the tissue in hypotonic medium results in the decrease in both the activity and the amount of the enzyme in tissue. Conversely, the addition of 1 mM alpha-methyl ornithine, an inhibitor of ornithine decarboxylase, causes augmentation of the activity and the amount of S-adenosyl-L-methionine decarboxylase, despite its inhibitory action on insulin-stimulated increase in the concentration of putrescine. These data suggest that putrescine can act as a 'negative' regulator of the enzyme in this system.
从小鼠乳腺中纯化得到的S-腺苷-L-甲硫氨酸脱羧酶（S-腺苷-L-甲硫氨酸羧基裂解酶，EC 4.1.1.50）的活性可被生理浓度的腐胺（Ka = 5×10⁻⁷ M）刺激。相反，通过外源添加腐胺或在低渗培养基中培养组织来提高培养的小鼠乳腺组织中腐胺的细胞内浓度，会导致组织中该酶的活性和含量均降低。相反，添加1 mM的α-甲基鸟氨酸（鸟氨酸脱羧酶的抑制剂），尽管其对胰岛素刺激的腐胺浓度升高有抑制作用，但会导致S-腺苷-L-甲硫氨酸脱羧酶的活性和含量增加。这些数据表明，在该系统中腐胺可作为该酶 的“负”调节剂。
