KAWANO Keiichi Hokkaido University, Division of Biological sciences, Asoociate professor, 理学部, 助教授 (10136492)
ISHIBASHI Kuniko Kyushu University, Faculty of Dentistry, Asistant professor, 歯学部, 助手 (50243952)
|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1995 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1994 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Hydrogen-deuterium exchange time was longer with Leu-8, Ala-9, Ala-10, Ala-11, Lys-13 in lysozyme which absorbed onto hydroxyapatite. It is thougt lysozyme is protected by absorbing onto hydroxyapatite, and the surface containing these residues is adsorbing site. Hydrogen-deuterium exchange time of Lys-13 was longer than others. So it is thought basic residues which have positive charges in lateral chain is adsorbing residue.
When lysozyme absorbed onto hydroxyapatite after preparing it by phosphoric acid, the adsorbing affinity was approximately 3 times but the adsorbing molecular number didn't change.
By these experiment we understood that the positive charge (amide group) of lysozyme adsorbs on the negative charge (phosphoric acid group) of hydroxyapatite.
On the other hand, Lys-1, Arg-5, Arg-14, Arg-128 existed around adsorbing site of lysozyme. The adsorbing affinity of acetylating lysozyme was weaker than native lysozyme. Because the amide group of lateral chain of those basic residue was acetylated and lysozyme lost the positive charge.
We understood that the amide group of Lys-1, Arg-5, Lys-13, Arg-14, Arg-128 lysozyme adsorbed on the phosphoric acid group of hydroxyapatite. And this adsorbing type was Langmuir-type by adsorbing isotherm experiment. Fortheremore each of lysozyme didnot have interaction, and lysozyme absorbs onto hydroxyapatite with monolayr.