Krajniak K G
Whitney Laboratory, University of Florida, St. Augustine 32086-8632.
Peptides. 1991 Nov-Dec;12(6):1295-302. doi: 10.1016/0196-9781(91)90210-g.
The pericardial organs and thoracic ganglia of the blue crab Callinectes sapidus were resected and extracted. The extracts were fractionated by HPLC and the fractions analyzed by a radioimmunoassay (RIA) to FMRFamide. Multiple peaks of immunoreactivity were present and one of these, upon fast atom bombardment mass spectrometry (FAB-ms) and microsequencing, yielded the sequence GYNRSFLRFamide. The amount of this peptide in each crab is between 7 and 13 pmol. Several incomplete sequences were also characterized, suggesting a precursor with multiple copies of peptides related to GYNRSFLRFamide might occur. The peptide caused a dose-dependent increase in heart rate; threshold was 10 to 30 nM, and the EC50 was 323 +/- 62 nM. A structure-activity study of GYNRSFLRFamide on the crab heart suggests that, for full potency, a peptide should be at least a heptapeptide with the sequence XXZFLRFamide, where X is any amino acid and Z is either asparagine or serine.
切除并提取了青蟹（Callinectes sapidus）的心包器官和胸神经节。提取物通过高效液相色谱法（HPLC）进行分级分离，各分级部分通过放射免疫分析法（RIA）分析FMRF酰胺。存在多个免疫反应峰，其中一个经快速原子轰击质谱法（FAB-ms）和微量测序后，得到序列GYNRSFLRF酰胺。每只螃蟹中这种肽的含量在7至13皮摩尔之间。还鉴定了几个不完整的序列，表明可能存在与GYNRSFLRF酰胺相关的多拷贝肽的前体。该肽引起心率呈剂量依赖性增加；阈值为10至30纳摩尔，半数有效浓度（EC50）为323±62纳摩尔。对青蟹心脏进行的GYNRSFLRF酰胺结构活性研究表明，要达到完全效力，该肽应为至少含XXZFLRF酰胺序列的七肽，其中X为任意氨基酸，Z为天冬酰胺或丝氨酸。
