Cheng C H, DeVries A L
Department of Physiology and Biophysics, University of Illinois, Urbana 61801.
Biochim Biophys Acta. 1989 Jul 27;997(1-2):55-64. doi: 10.1016/0167-4838(89)90135-0.
The antarctic eel pout, Austrolycicthys brachycephalus, synthesizes two predominant antifreeze peptides (AFPs) which, based on purification yields, make up about 94 and 6%, respectively, of the antifreezes in its serum. The amino acid sequences of these two AFPs, AB1 and AB2, were determined using automated sequencing, and compositional analyses of peptide fragments from enzymatic digests, and verified by molecular masses obtained with Fast Atom Bombardment Mass spectrometry. Substantial homologies in amino acid sequence exist between the AFPs of Austrolycicthys and those of other Southern and Northern eel pouts. 72% of the residues of AB1, and 84% of AB2, are identical to those of an AFP from another antarctic eel pout, Rhigophila dearborni. Between AB1 and AB2, 83% of the residues are identical. Secondary structure data based on circular dichroism studies indicated AB1 to be a random chain, but a sharp thermal transition of CD spectra around 30 degrees C suggested the presence of definite secondary or tertiary structure.
南极粘鱼，短头澳粘鱼，能合成两种主要的抗冻肽（AFP），根据纯化产量，这两种抗冻肽分别约占其血清中抗冻剂的94%和6%。利用自动测序、酶解肽片段的组成分析以及快原子轰击质谱法获得的分子量对这两种抗冻肽AB1和AB2的氨基酸序列进行了测定，并得到了验证。南极粘鱼的抗冻肽与其他南极和北极粘鱼的抗冻肽在氨基酸序列上存在大量同源性。AB1的72%的残基和AB2的84%的残基与另一种南极粘鱼——迪氏嗜冷鱼的一种抗冻肽的残基相同。在AB1和AB2之间，83%的残基是相同的。基于圆二色性研究的二级结构数据表明AB1是无规链，但在30摄氏度左右CD光谱的急剧热转变表明存在确定的二级或三级结构。
