Hogan J S, Duthie A H, Pankey J W
J Dairy Sci. 1986 Sep;69(9):2424-7. doi: 10.3168/jds.S0022-0302(86)80682-8.
Keratin from 507 excised teats was pooled, separated into three samples, and analyzed for fatty acid composition of extracellular and intracellular lipids. Mean weight of keratin collected per teat canal was 8.97 mg. Extracellular lipids were recovered in petroleum ether. Intracellular lipids were extracted in chloroform: methanol (2:1, vol/vol) solution. Average keratin wet weight of extracellular and intracellular lipid fractions were 37.1 and 21.9 mg/g, respectively. Polar and nonpolar lipids were present in both fractions. Predominant fatty acids in extracellular and intracellular lipids were C16, C18:1, and C18. Extracellular lipids contained greater concentrations of C4 to C18:1 fatty acids than did intracellular lipids. Percent of total fatty acid weight comprised by each of C4, C10, C12 and C14 was also significantly greater in extracellular than intracellular fractions. Intracellular lipids contained a greater concentration and percent total fatty acid content comprised by C18:2 than extracellular lipids. Data suggest lipids accessible at the keratin interface are in part of milk fat origin.
收集了507个切除乳头的角蛋白，将其合并为三个样本，并分析细胞外和细胞内脂质的脂肪酸组成。每个乳头管收集的角蛋白平均重量为8.97毫克。细胞外脂质用石油醚回收。细胞内脂质用氯仿：甲醇（2:1，体积/体积）溶液提取。细胞外和细胞内脂质部分的角蛋白平均湿重分别为37.1和21.9毫克/克。两个部分中均存在极性和非极性脂质。细胞外和细胞内脂质中的主要脂肪酸为C16、C18:1和C18。细胞外脂质中C4至C18:1脂肪酸的浓度高于细胞内脂质。细胞外部分中C4、C10、C12和C14各自占总脂肪酸重量的百分比也显著高于细胞内部分。细胞内脂质中C18:2的浓度和占总脂肪酸含量的百分比高于细胞外脂质。数据表明，在角蛋白界面可获取的脂质部分来源于乳脂肪。
