25aC07
交流電界によるウシ血清アルブミンの立体構造の変化
Conformational Change in Bovine Serum Albumin by AC Electric Field
奥村賢直1，山田和樹1，八重樫大朗1，高橋克幸1，井上諭宜2，會澤純雄3，首藤文榮2，高木浩一1
OKUMURA Takamasa, YAEGASHI Taro, YAMADA Kazuki, TAKAHASHI Katsuyuki, INOUE Yuki,
AISAWA Sumio, SYUTO Bunei, TAKAKI Koichi
岩手大 工学部 電気電子・情報システム工学科
2
岩手大 地域連携推進センター
3
岩手大 工学部 応用化学・生命工学科
1
Dep. of Electrical Eng. and Comp. Sci., Iwate Uni., Japan
2
Cent. for Regional Collab. in Res. and Edu., Iwate Uni., Japan3
Dep. of Chem. and Bioeng., Iwate Uni., Japan1

4. ConclusionInfluence of an AC electric field on conformation ofbovine serum albumin (BSA) was investigated. As aresult the process of trypsin digestion of BSA wasaffected by the application of the AC electric field,
suggesting that the conformation of BSA was changedby the application of the AC electric field.

Fig. 1. SDS-PAGE pattern for BSA digested by trypsin.
0.018
0.016
0.014
0.012
0.010
0.008
0.006
0.004
0.002
0.000

With the AC electric field
Without the AC electric field

0.750

0.700

0.650

0.600

0.550

0.500

0.450

Peak of BSA

0.400

Normalized OD Value

1. Introduction
An AC electric field seems to inhibit protein
digestion of the food material in our recent study1.
The inhibition of protein digestion is caused byconformational changes of membrane proteins. In thisstudy the influence of an AC electric field in theconformational change of protein molecule wasinvestigated by using bovine serum albumin (BSA) asa model material.
2. Experimental
BSA solution was divided into two groups. They
were kept in an incubator at 4°C for 72 hours. Onewas preserved with an AC electric field and the otherwas preserved without the AC electric field. The
amplitude of the AC electric field was about 66.7
kV/m with a frequency of 50 Hz. When theconformational change of the BSA molecule isinduced its sensitivity to trypsin will be changed
because the trypsin is highly specific to the C-terminalsides of lysine and arginine residues of the protein
molecule. Then, the kinds and amounts of tryptic
peptides will be changed. The specimen was digested
by trypsin at 30°C for predetermined time. The tryptic
peptides were analyzed with SDS-PAGE. We usede-PAGEL (E-T 520L, ATTO), a silver stain reagent(2D-Silver Stain Reagent II, Cosmo Bio) to detect
protein and a densitometer (GS-800, Bio-Rad) toanalyze protein bands.
3. Results
Figure 1 shows the SDS-PAGE pattern. The bands
with an arrow in Fig. 1 are of BSA. Fig. 2 showsdensitograms of specimens digested for 30 minutes.
The relative absorbance of BSA band without the ACelectric field is lower than that with the AC electricfield. Peaks in the gray region in Fig. 2 show thetryptic peptides. OD value on arrowed peak of thespecimen without the AC electric field is higher thanthat with the AC electric field. These results strongly
suggest that the conformational change in BSA isinduced by the application of the AC electric field.
These results correspond to [2].

Relative front Value

Fig. 2. SDS-PAGE analysis of specimens digested for 30
minutes.

References[1] T. Ito et al., Preservation of Fresh Food Using AC

Electric Field, J. Adv. Oxid. Technol, Vol. 17, No. 2,
pp. 1-5, 2014[2] I. Bekard and D.E. Dunstan: “Electric field inducedchanges in protein conformation”, Soft Matter, 10(2014) pp. 431-437.