Preparation of recombinant proteins in milk.

Using transgenic animals as the source of recombinant proteins has several specific advantages. Large amounts of proteins can be obtained, essentially from milk. These proteins are often properly processed. They are in a number of cases correctly folded, assembled, cleaved, glycosylated, gamma-carboxylated, and so on. Purification of recombinant proteins from milk is not a particularly difficult task. The level of expression of foreign genes in milk cannot be predicted in all cases and appropriate vectors must be used. Generation of transgenic mice is popular but their production is quite limited. Transgenesis in larger animals, rabbits and farm animals, is achieved essentially by a few companies. Some recombinant proteins may be found in blood circulation and alter animal health. Milk from transgenic animals has become a quite attractive alternative to other sources of recombinant proteins.