Reducing 2-DGE of rennet casein fraction from heat-treated milk visualised by colloid Coomassie Brilliant Blue G-250 staining. The conditions of the 2-DGE were as described in Figure 1 legend, except that this gel was run at reducing conditions as described in Materials and Methods. The sample analysed in Figures 1 and 2 was from the same individual cow. The positions of protein spots referred to in Tables I and II are indicated by an arrow and by their identification number in the image analysis of the reduced gels. The positions of major caseins assigned according to  are indicated in white.