Affiliations: School of Life Sciences and Biotechnology, Korea
University, Seoul 136-701, Korea | Graduate School of East-West Medical Science, Kyung
Hee University, Suwon 449-701, Korea | School of Biotechnology and Bioengineering, Kangwon
University, Chunchon 200-701, Korea | SD BNI Co., Ltd., Ansan 425-100, Korea
Note: [] Address for correspondence: Sang-Yun Choi, Ph.D. School of Life
Sciences and Biotechnology, Korea University, 5-1 Anam-dong, Sungbuk-gu, Seoul
136-701, Korea. Tel.: +82 2 3290 3441; Fax: +82 2 927 3091; E-mail:
sychoi@korea.ac.kr
Abstract: Calcium homeostasis in the human body is maintained primarily via
the absorption of calcium through the intestine. In order to maintain an
efficient absorption of calcium with minimal calcium loss due to the formation
of calcium phosphate precipitates in the small intestinal lumen, we developed a
calcium-binding mediator using peptides derived from isolated soybean protein
(ISP). ISP was modified via tryptic digestion and chemical phosphorylation
using sodium trimetaphosphate, thereby generating soybean phosphopeptides
(SPP), and this was followed by conducting a binding reaction with calcium
chloride. We have established an optimized procedure and reaction conditions
for maximal phosphorylation and calcium binding. Consequently, the
phosphorylation of soybean peptides resulted in considerable improvement in
their calcium binding activities. Next, we demonstrated that SPP was able to
render calcium ions resistant to precipitate formation with inorganic
phosphates, which suggested the enhancement of calcium bioavailability.
Finally, we noted that the addition of calcium-bound SPP induced an increase in
cytosolic calcium concentration in the intestinal Caco-2 cells, due to an
influx of calcium. These findings provide a new basis by which we may assess
the possibility that SPP, as a potent calcium carrier, can be utilized in the
prevention of poor absorption of dietary calcium in animals.
