GROSS J
J Exp Med. 1958 Aug 1;108(2):215-26. doi: 10.1084/jem.108.2.215.
Precipitation (or gelation) of collagen from cold neutral salt solution induced by warming was shown to be reversible on subsequent cooling. The degree of reversibility of heat precipitation rapidly diminished with time of incubation at 37°C. For calf skin collagen (acetic acid-extracted) and guinea pig skin collagen (crude NaCl extract) in neutral salt solutions (Γ/2 = 0.45) roughly 90 per cent of newly formed gel redissolved on cooling at 2°C.; less than 20 per cent redissolved on cooling gels previously maintained at 37°C. for 24 hours. At physiologic ionic strength the same preparations exhibited much more rapid development of irreversible precipitation, but the same time dependence was clearly evident. Highly purified collagen from crude saline extracts of guinea pig skin exhibited the same phenomenon although the quantitative aspects were somewhat different.
研究表明，由升温诱导的冷中性盐溶液中胶原蛋白的沉淀（或凝胶化）在随后冷却时是可逆的。热沉淀的可逆程度会随着在37°C孵育时间的增加而迅速降低。对于小牛皮肤胶原蛋白（乙酸提取物）和豚鼠皮肤胶原蛋白（粗氯化钠提取物），在中性盐溶液（Γ/2 = 0.45）中，大约90%新形成的凝胶在2°C冷却时会重新溶解；而冷却之前在37°C保持24小时的凝胶，重新溶解的比例不到20%。在生理离子强度下，相同的制剂表现出不可逆沉淀的发展要快得多，但时间依赖性同样明显。来自豚鼠皮肤粗盐水提取物的高度纯化胶原蛋白也表现出相同的现象，尽管在定量方面有所不同。
