Physical Chemistry of Foods

FIGURE7.1 Illustration of some aspects of the primary structure of two proteins,b-lactoglobulin (genetic variant B) andb-casein
(variant A2). The straight line denotes the amino acid sequence, from the N-terminal end on the left-hand side to the C-terminal end.
Solid squares on the line denote hydrophobic residues (Leu, Ile, Val, Phe, and Trp), a cross ( 6 ) indicates a Pro residue, and the
vertical lines denote charge at a pH of about 6.6 (positive upwards, negative downwards); the longer lines denote serine-phosphate
ðz&
1 : 5 Þ, the shorter ones histidineðz&þ 0 : 5 Þ. Cysteine residues are denoted by S, and 22 S 22 S 22 bridges by connecting lines.