α-lactalbumin , a milk protein, is the regulatory subunit of lactose
synthase. In the mammary gland, α-lactalbumin changes the substrate
specificity of galactosyltransferase from N-acetylglucosamine to glucose.
Lysozymes (EC 188.8.131.52)  act as bacteriolytic enzymes by hydrolyzing the
β(1->4) bonds between N-acetylglucosamine and N-acetylmuramic acid in the
peptidoglycan of prokaryotic cell walls. There are at least five different
classes of lysozymes [3,4]: C (chicken type), G (goose type), phage-type (T4),
fungi (Chalaropsis), and bacterial (Bacillus subtilis) but there are few
similarities in the sequences of the different types of lysozymes.
α-lactalbumin and lysozyme C are evolutionary related . Around 35 to
40% of the residues are conserved in both proteins as well as the positions of
the four disulfide bonds (see the schematic representation). The pattern for
this family of proteins includes three cysteines involved in two of these
disulfide bonds (the first cysteine is linked to the third one).
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