Authors : H. K. Cheung , J. Mei , T. Wang and R. J. Xu
Abstract: It is well known that animal milk contains various bioactive compounds, such as immunoglobulins, hormones and growth factors. The present study reports the detection of a new bioactive compound, betaglycan, in porcine milk. The concentration of betaglycan in the milk, determined by a specific enzyme-linked immuno-sorben assay, ranged between 0.25 and 0.41 mg ml-1. The concentration was highest in the colostrum and it declined with the progress of lactation. Further studies with Western blot analysis or gel filtration in combination with deglycosylation enzyme treatment demonstrated that the compound consisted of glycosaminoglycan chains and a core protein of about 110 kDa. Pre-treatment of the milk samples with the reducing agent, 2-mercaptoethanol, revealed that the core protein contained disulfide bonds. These findings indicate that the soluble betaglycan detected in porcine milk has a property similar to that of the ectodomain of the membrane-anchored betaglycan. It was also observed that the soluble betaglycan detected in porcine milk was capable of binding TGF-b. It is speculated that the milk-borne betaglycan may play a role in modulating TGF-b activity; the latter has also been reported in porcine milk.
H. K. Cheung , J. Mei , T. Wang and R. J. Xu , 2004. Detection and Characterization of Soluble Betaglycan in Porcine Milk . Journal of Animal and Veterinary Advances, 3: 278-284.