1. Characterization of tryptic hydrolysis of alpha-lactalbumin/saponin mixture and structural change of alpha-lactalbumin interacting with soybean saponin.
- Author
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Shimoyamada M, Okada Y, Watanabe K, and Yamauchi R
- Subjects
- Animals, Cattle, Circular Dichroism, Hydrolysis, Magnetic Resonance Spectroscopy, Milk chemistry, Peptides chemistry, Protein Structure, Tertiary, Glycine max chemistry, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Trypsin chemistry, Lactalbumin chemistry, Saponins chemistry
- Abstract
Bovine milk alpha-lactalbumin (alpha-La) was mixed with soybean saponin, and the resulting mixture was hydrolyzed by trypsin. Saponin increased the tryptic-hydrolysis level of alpha-La only at relatively high phosphate buffer concentrations (> or = 0.05 M). T(1) experiments with acetylated soybean saponin demonstrated that there were some interactions between alpha-La and saponin not only at high concentrations of phosphate buffers but even at low concentrations as well. Circular dichroism spectra of alpha-La showed that the tertiary structure of alpha-La was changed through interactions with saponin only at high buffer concentrations. Furthermore, by analyzing the tryptic peptides from an alpha-La/saponin mixture, hydrolyzing rates at all or some of K5, R10, and K16 of alpha-La were accelerated by saponin interactions. The increase in the tryptic hydrolysis of alpha-La by saponin addition was considered due to modification of the tertiary structure of alpha-La by saponin.
- Published
- 2005
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