Kuroki M, Shinoda T, Takayasu T, Koga Y, Matsuoka Y
Mol Immunol. 1982 Mar;19(3):399-406. doi: 10.1016/0161-5890(82)90205-x.
Normal fecal antigen-1 (NFA-1), which is a carcinoembryonic antigen (CEA)-related glycoprotein with a mol. wt of 20,000-30,000, was purified from normal adult feces by immuno-adsorption, gel filtration and ion exchange chromatography. Highly purified NFA-1 was partially cross-reactive with CEA but antigenically unrelated to nonspecific cross-reacting antigen (NCA) which was also cross-reactive with CEA. NFA-1 also had a unique determinant not present in CEA or other related antigens including NCA. In a solid-phase RIA system, the reactivity of NFA-1 with a specific anti-CEA antiserum was much stronger than that of NCA. Although digestion with Pronase E did not affect the antigenicity of NFA-1, reduction and alkylation destroyed its antigenic reactivity. The total amount of carbohydrate in NFA-1 was 13.3%, compared to 52.4% in CEA and 21.6% in NCA. The amino acid composition of NFA-1 was similar to that of CEA. The sequence of the first 10 NH2-terminal amino acids in NFA-1 was Ala-Glu-Pro-Pro-Lys-Pro-Phe-Ile-(Thr)-Ser. This was totally different from that of the first NH2-terminal amino acids of CEA isolated from tumor tissue.
正常粪便抗原-1（NFA-1）是一种分子量为20,000 - 30,000的癌胚抗原（CEA）相关糖蛋白，通过免疫吸附、凝胶过滤和离子交换色谱法从正常成人粪便中纯化得到。高度纯化的NFA-1与CEA有部分交叉反应，但与同样与CEA交叉反应的非特异性交叉反应抗原（NCA）在抗原性上无关。NFA-1还具有CEA或其他相关抗原（包括NCA）中不存在的独特决定簇。在固相放射免疫分析系统中，NFA-1与特异性抗CEA抗血清的反应性比NCA强得多。虽然用链霉蛋白酶E消化不影响NFA-1的抗原性，但还原和烷基化会破坏其抗原反应性。NFA-1中碳水化合物的总量为13.3%，而CEA中为52.4%，NCA中为21.6%。NFA-1的氨基酸组成与CEA相似。NFA-1中前10个氨基末端氨基酸的序列为Ala-Glu-Pro-Pro-Lys-Pro-Phe-Ile-(Thr)-Ser。这与从肿瘤组织中分离的CEA的第一个氨基末端氨基酸序列完全不同。
