Leipold B, Richter D
Hoppe Seylers Z Physiol Chem. 1979 Oct;360(10):1453-6. doi: 10.1515/bchm2.1979.360.2.1453.
The oligopeptides beta- and delta O-endorphin were isolated from porcine and bovine pituitary respectively. Their opiate activity was determined in the guinea pig ileum and compared to that of the pentapeptide methionine-enkephalin and morphine. The rank order of opioid activity was found to be: morphine greater than beta-endorphin = Met-enkephalin greater than delta O-Endorphin which lacks the four C-terminal amino acids of beta-endorphin displayed 60% of the activity of beta-endorphin. These results indicate, that C-terminal amino acids contribute little to the affinity of beta-endorphin for opiate receptors in the guinea pig ileum.
寡肽β-内啡肽和δ-内啡肽分别从猪和牛的垂体中分离出来。它们的阿片样活性在豚鼠回肠中测定，并与五肽甲硫氨酸脑啡肽和吗啡的活性进行比较。发现阿片样活性的顺序为：吗啡＞β-内啡肽=甲硫氨酸脑啡肽＞δ-内啡肽（δ-内啡肽缺少β-内啡肽的四个C末端氨基酸，其活性为β-内啡肽的60%）。这些结果表明，C末端氨基酸对β-内啡肽与豚鼠回肠中阿片受体的亲和力贡献不大。
