Era S, Ashida H, Nagaoka S, Inouye H, Sogami M
Int J Pept Protein Res. 1983 Sep;22(3):333-40. doi: 10.1111/j.1399-3011.1983.tb02099.x.
Bovine plasma albumin (BPA) showed the acid-induced two-step transition, the N-F transition and acid-expansion. Changes in fractions of alpha-helix (f alpha), beta-form (f beta) and unordered form (fR) in the acid-induced isomerization of BPA were studied using the method of Chen et al. (1972) with two constraints: sigma fi = 1, 0 less than or equal to fi less than or equal to 1. pH-profiles of f alpha and fR showed the two-step change, one corresponding to the N-F transition and the other to the acid-expansion in 0.10 M KCl and in 0.02 M NaClO4. pH-profile of f beta showed one-step change, correlating to the later part (lower pH side) of the N-F transition. The N-F transition might thus involve the helix leads to beta and helix leads to coil transitions.
牛血浆白蛋白（BPA）呈现出酸诱导的两步转变，即N-F转变和酸膨胀。采用Chen等人（1972年）的方法，在两个约束条件下研究了BPA酸诱导异构化过程中α-螺旋（fα）、β-形式（fβ）和无序形式（fR）的分数变化：∑fi = 1，0≤fi≤1。fα和fR的pH曲线呈现出两步变化，一步对应N-F转变，另一步对应在0.10 M KCl和0.02 M NaClO4中的酸膨胀。fβ的pH曲线呈现出一步变化，与N-F转变的后半部分（较低pH侧）相关。因此，N-F转变可能涉及螺旋向β转变和螺旋向无规卷曲转变。
