Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan.
J Microbiol Biotechnol. 2010 Oct;20(10):1436-9. doi: 10.4014/jmb.1004.04043.
Many studies have clarified that poly(gamma-glutamic acid) (PGA) increases the solubility of Ca(2+), suggesting that PGA enhances calcium absorption in small intestine. However, there has been no report on the specific interaction between PGA and Ca(2+) in water. We studied the aqueous solution properties of PGA calcium salt (PGA-Ca complex). The chelating ability and binding strength of PGA for Ca(2+) were evaluated. PGA-Ca complex was soluble in water in contrast with the insolubility of poly(acrylic acid) (PAA) calcium salt and the chelating ability of PGA for Ca(2+) was almost the same than that of PAA. The globular conformation of PGA-Ca complex in water was estimated by SEC and viscosity measurements. The chelation of PGA for Ca(2+) was examined by ¹H NMR. The present study showing the characteristics of PGA-Ca complex will provide useful information of the calcium absorption by PGA in vivo.
许多研究已经阐明，聚（γ-谷氨酸）（PGA）增加了 Ca（2+）的溶解度，表明 PGA 增强了小肠对钙的吸收。然而，关于 PGA 和 Ca（2+）在水中的具体相互作用还没有报道。我们研究了 PGA 钙盐（PGA-Ca 复合物）的水溶液性质。评估了 PGA 对 Ca（2+）的螯合能力和结合强度。PGA-Ca 复合物可溶于水，而聚（丙烯酸）（PAA）钙盐不溶于水，PGA 对 Ca（2+）的螯合能力几乎与 PAA 相同。通过 SEC 和粘度测量估计了 PGA-Ca 复合物在水中的球形构象。通过 ¹H NMR 检查了 PGA 对 Ca（2+）的螯合作用。本研究显示了 PGA-Ca 复合物的特性，将为 PGA 在体内吸收钙提供有用的信息。
