Yoshida S
Department of Applied Biological Science, Horishima University, Japan.
J Dairy Sci. 1992 Apr;75(4):958-61. doi: 10.3168/jds.S0022-0302(92)77836-9.
The binding ability of bovine milk caseins with mutagenic heterocyclic amines was investigated. Binding was determined with 2 mg of casein and 20 micrograms of heterocyclic amine in .40 ml of pH 7.4, 50 mM phosphate buffer, at 37 degrees C, in a shaker for 10 min. The unbound heterocyclic amine in protein-free ultrafiltrate was analyzed by HPLC. The binding ability of whole casein, alpha s-casein, beta-casein, and kappa-casein, respectively, was 90.08, 83.06, 90.92, and 96.70% with 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole; 85.48, 51.54, 63.62, and 82.71% with 3-amino-1-methyl-5H-pyrido[4,3-b]indole; and 87.03, 59.77, 97.04, and 88.30% with 2-amino-6-methyldipyrido[1,2-a:3',2'-d]-imidazole. Higher binding of 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 3-amino-1-methyl-5H-pyrido[4,3-b]indole to alpha s-casein, beta-casein, and kappa-casein was observed at pH above 7.4, and the binding was inhibited at pH below 6.5. The maximum binding of 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole to these caseins was at pH 6.6 and 7.4. The binding was inhibited at alkaline pH above 8.5 and acidic pH below 6.5.
研究了牛乳酪蛋白与诱变杂环胺的结合能力。在37℃下，于0.40 ml pH 7.4、50 mM磷酸盐缓冲液中，将2 mg酪蛋白与20微克杂环胺混合，在振荡器中振荡10分钟，测定结合情况。通过高效液相色谱法分析无蛋白超滤液中未结合的杂环胺。全酪蛋白、αs-酪蛋白、β-酪蛋白和κ-酪蛋白与3-氨基-1,4-二甲基-5H-吡啶并[4,3-b]吲哚的结合能力分别为90.08%、83.06%、90.92%和96.70%；与3-氨基-1-甲基-5H-吡啶并[4,3-b]吲哚的结合能力分别为85.48%、51.54%、63.62%和82.71%；与2-氨基-6-甲基二吡啶并[1,2-a:3',2'-d]咪唑的结合能力分别为87.03%、59.77%、97.04%和88.30%。在pH高于7.4时，观察到3-氨基-1,4-二甲基-5H-吡啶并[4,3-b]吲哚和3-氨基-1-甲基-5H-吡啶并[4,3-b]吲哚与αs-酪蛋白、β-酪蛋白和κ-酪蛋白的结合更高，而在pH低于6.5时结合受到抑制。2-氨基-6-甲基二吡啶并[1,2-a:3',2'-d]咪唑与这些酪蛋白的最大结合在pH 6.6和7.4。在碱性pH高于8.5和酸性pH低于6.5时结合受到抑制。
