Pelissier J P, Dubos F, Daburon F
Reprod Nutr Dev (1980). 1981;21(4):513-8.
Radioactive ovine casein was obtained by injecting 100 microCi of 14C-Ser into the jugular vein of an ewe. The milk collected 17 and 24 h after this injection contained 12 p. 100 of the radioactivity injected in protein form. The seryl residues were specificially labelled. This casein was used as the only protein source fed to axenic rats; 0.30 p. 100 of the tracer ingested was found in the feces of those rats. Since phosphoserine represented 25 p. 100 of the total casein seryl residues, the phosphopeptides may not be selectively unabsorbable.
通过向一只母羊的颈静脉注射100微居里的¹⁴C-丝氨酸来获得放射性羊酪蛋白。在此次注射后17小时和24小时收集的乳汁中，以蛋白质形式存在的放射性占注射量的12%。丝氨酰残基被特异性标记。这种酪蛋白被用作无菌大鼠唯一的蛋白质来源；在这些大鼠的粪便中发现摄入的示踪剂中有0.30%。由于磷酸丝氨酸占酪蛋白总丝氨酰残基的25%，磷酸肽可能并非选择性地不可吸收。
