Ulman L G, Potter E K, McCloskey D I
Prince of Wales Medical Research Institute, Randwick, Sydney, Australia.
Regul Pept. 1993 Mar 5;44(1):85-92. doi: 10.1016/0167-0115(93)90132-r.
Galanin (GAL), 29 amino acid peptide, has previously been shown to inhibit cardiac vagal action, and to cause a fall in systemic blood pressure in anaesthetised cats, at a dose of 6.2 nmol/kg. Here, the biological activity of exogenous GAL fragments was assessed in anaesthetised cats. GAL 1-16 at a dose equimolar with the full GAL 1-29 peptide (6.2 nmol/kg) and at a dose five times the molar dose of GAL 1-29 (31 nmol/kg), was found to be biologically active although the effects were less than that of the full peptide. GAL 1-15 at doses up to 10-times the molar dose of GAL 1-29, however, was not active, suggesting that amino acid 16, isoleucine, is critical for activity. In addition, GAL 15-29 and 21-29 showed no biological activity at doses up to 10-times the molar dose of GAL 1-29. These results suggest that the N-terminal rather than the C-terminal end of the GAL molecule is the one responsible for most of GAL's biological activity in this preparation.
甘丙肽（GAL）是一种由29个氨基酸组成的肽，先前的研究表明，在麻醉猫中，剂量为6.2 nmol/kg时，它能抑制心脏迷走神经活动，并导致全身血压下降。在此，我们评估了外源性GAL片段在麻醉猫中的生物活性。发现与完整的GAL 1-29肽等摩尔剂量（6.2 nmol/kg）以及GAL 1-29摩尔剂量五倍（31 nmol/kg）的GAL 1-16具有生物活性，尽管其作用小于完整肽。然而，剂量高达GAL 1-29摩尔剂量10倍的GAL 1-15没有活性，这表明第16位氨基酸异亮氨酸对活性至关重要。此外，在剂量高达GAL 1-29摩尔剂量10倍时，GAL 15-29和21-29没有显示出生物活性。这些结果表明，在该制剂中，GAL分子的N端而非C端是其大部分生物活性的主要来源。
