US EPA

1490312 

Journal Article 

Hydrophobicity of bovine serum albumin and ovalbumin determined using uncharged (PRODAN) and anionic (ANS(-)) fluorescent probes 

Haskard, CA; Li-Chan, ECY 

1998 

Yes 

Journal of Agricultural and Food Chemistry
ISSN: 0021-8561
EISSN: 1520-5118 

46 

7 

2671-2677 

English 

10.1021/jf970876y 

WOS:000074993100041 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001296380&doi=10.1021%2fjf970876y&partnerID=40&md5=8db2d755305e6daf52bb6fcb3aa6b64e
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The influence of ionic interactions on quantitation of
protein surface hydrophobicity was assessed by comparing the protein binding of an uncharged
fluorescent probe, 6-propionyl-2-(N,N-dimethylamino)naphthalene (PRODAN), with that of an anionic
probe, 1-(anilino)naphthalene-8-sulfonate (ANS(-)). Binding constants for the protein-probe
complexes involving bovine serum albumin (BSA) and ovalbumin (OVA) in phosphate buffer (pH 7.0, I
= 0.01 M) at 30 degrees C were fluorometrically determined to be KP-BSA = (1.00 +/- 0 01) x 10(6)
M-1 and KP-OVA = (4.2 +/- 0.1) x 10(3) M-1, respectively, for PRODAN, compared to KA-BSA = (6.21
+/- 0.04) x 10(6) M-1 and KA-OVA = (1.97 +/- 0.09) x 10(3) M-1, respectively, for ANS(-). A
procedure was established using PRODAN to determine protein surface hydrophobicity (So) values
from the initial slope of relative fluorescence intensity versus protein concentration plots, and
the results were compared to S-0 values measured using ANS(-). Increasing ionic strength up to
1.0 M decreased the S-0 values of BSA measured by ANS(-), increased So of BSA measured by PRODAN
and of OVA measured by ANS(-), and had no significant effect on the S-0 of OVA measured by
PRODAN. These results demonstrate the importance of considering charge effects when determining
protein surface hydrophobicity. 

protein hydrophobicity; fluorescent probe; electrostatic interactions; PRODAN; ANS