Bovine β-Casein Expressed in Transgenic Mouse Milk Is Phosphorylated and Incorporated into Micelles

Transgenic mammalian species, generated by somatic cell cloning, in biomedicine, biopharmaceutical industry and human nutrition/dietetics - recent achievements

“…Relatively small changes in casein ratios can affect the micelle structure and thus can have substantial effects on the functional properties of milk. For this reason, a higher casein concentration would not only increase a valuable milk component but could simultaneously improve milk characteristics (Hitchin et al 1996, Choi et al 2001. Together with fat, casein proteins are responsible for the specific white chalky children's milk "mustache".…”

“…Introduction of additional genomic sequences encoding protease (chymosin) cleavage sites into the casein gene locus can cause the improvement of cheese-ripening process. On the other hand, deletion from the β-casein gene of exon regions responsible for the formation of the protease (plasmin) site in its translation product can induce an increase in β-casein emulsifying properties as well as elimination of the bitter flavour in produced cheese (Hitchin et al 1996, Laible et al 2007, Pampel et al 2008. Introduction of supplementary functional copies of genes encoding regulatory immunoproteins of the milk such as lysozyme, lactoferrin or lysostaphin can enhance the antimicrobial immunosupressive activity of such genetically-modified milk (Hyvö nen et al 2006, Yu et al 2006).…”

Insertion of a casein kinase recognition sequence induces phosphorylation of ovine β-lactoglobulin in transgenic mice

“…Samples were prepared as described previously (Hitchin et al, 1996). BLG was purified from fresh, pooled sheep milk (Aschaffenburg and Drewry, 1957), checked for purity by gel and Western blot analysis and the protein content determined by the micro-Kjeldahl technique (McClenaghan et al, 1995).…”

“…Proteins were desalted by reversed-phase HPLC (Hitchin et al, 1996) and freeze-dried. After redissolving in acetonitrile and H 2 O (1:1, v/v) containing 0.1% trifluoroacetic acid, the proteins were mixed and their molecular masses determined by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry using an α-cyano-4-hydroxycinnamic acid matrix (Hitchin et al, 1996).…”

“…Proteins were desalted by reversed-phase HPLC (Hitchin et al, 1996) and freeze-dried. After redissolving in acetonitrile and H 2 O (1:1, v/v) containing 0.1% trifluoroacetic acid, the proteins were mixed and their molecular masses determined by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry using an α-cyano-4-hydroxycinnamic acid matrix (Hitchin et al, 1996). Infrared spectroscopy Infrared spectra were recorded at room temperature on KBr discs containing~0.5% of freeze-dried protein or peptide in the mid-infrared region (4000-400 cm -1 ) at a spectral resolution of 2 cm -1 and with triangular apodization using a Mattson Galaxy 7000 spectrophotometer.…”