Sheep, transgenic, milk from

High expression levels of proteins are potentially attained. In many instances, the level of expression exceeds 1 g protein/litre milk. In one case, initial expression levels of 60 g l-1 were observed, which stabilized at 35 g L1 as lactation continued (the expression of the arantitrypsin gene, under the influence of the ovine P-lactoglobulin promoter, in a transgenic sheep). Even at expression levels of 1 g L1, one transgenic goat would produce a similar quantity of product in 1 day as would be likely recoverable from a 50-1001 bioreactor system. 

With successful advances in research, several other recombinant proteins of pharmaceutical interest have been developed from the milk of transgenic animals. In this context, some human proteins have already been expressed with success. Products such as insulin and growth hormone have also been obtained from the milk of transgenic cows, sheep, or goats (Margawati, 2003). 

Harris DP, Andrews AT, Wright G, et al. The application of aqueous two-phase systems to the purification of pharmaceutical proteins from transgenic sheep milk. Bioseparation, 1997 7(1) 31-37. 

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