TABLE 2.

ANS fluorescence properties of PDI, abb′x, and their mutants

Protein	Enhancement factora
PDI	8.3 ± 1
I272A PDI	5.5 ± 0.7
L343A PDI	7.3 ± 0.8
abb′x	6.7 ± 0.7
I272A abb′x	2.6 ± 0.3
L343A abb′x	6.6 ± 0.6

^a Enhancement factor = (F(protein + buffer + ANS) − F(protein + buffer))/(F(ANS + buffer) − F(buffer)), where F is the fluorescence intensity at 480 nm. Data were expressed as the mean ± S.D. (n = 3).