Pang P K, Yang M C, Kenny A D, Tenner T E
Clin Exp Hypertens A. 1982;4(1-2):189-99. doi: 10.3109/10641968209061584.
The synthetic fragment of bovine PTH [bPTH-(1-34)] had direct vasodilatory action in the coronary, renal, hepatic and some visceral vascular beds. The vascular action of bPTH-(1-34) was separable from its hypercalcemic action. We attempted to identify the amino acid sequence responsible for this vascular action. The methionines in positions 8 and 18 were not necessary for vascular relaxation since [Nle8, Nle18, Tyr34]-bPTH-(1-34) was active. However, when these methionine residues were oxidized, the vascular action of this peptide disappeared. This would suggest conformational changes of this oxidized peptide, resulting in loss of activity. Adjacent basic amino acids in positions 25, 26 and 27 may play an important role in the hypotensive action of peptides. Other hypotensive peptides such as neurotensin, xenopsin and VIP which also possess adjacent basic amino acids but are not known to be vasoactive were also hypotensive in our assays.
牛甲状旁腺激素的合成片段[bPTH-(1-34)]在冠状动脉、肾动脉、肝动脉及一些内脏血管床具有直接的血管舒张作用。bPTH-(1-34)的血管作用与其高钙血症作用是可分离的。我们试图确定负责这种血管作用的氨基酸序列。第8位和第18位的甲硫氨酸对于血管舒张并非必需，因为[Nle8, Nle18, Tyr34]-bPTH-(1-34)具有活性。然而，当这些甲硫氨酸残基被氧化时，该肽的血管作用消失。这表明这种氧化肽发生了构象变化，导致活性丧失。第25、26和27位相邻的碱性氨基酸可能在肽的降压作用中起重要作用。其他降压肽，如神经降压素、异视紫质和血管活性肠肽，它们也具有相邻的碱性氨基酸，但未知具有血管活性，在我们的实验中也具有降压作用。
