Lactose synthase system interactions

C. Interactions of Galactosyltransferase and a-LactaUmmin in the Lactose Synthase System... 

It has been conventional wisdom that lysozyme is not active in the lactose synthase system and that a-lactalbumin does not have lytic activity. The essential residues for interaction of specifier protein with ga-lactosyltransferase have not yet been unequivocably defined, nor has the role of Ca(II) in this system. Thus, it is not, at present, possible to rule out weak specifier activity for lysozyme in the lactose synthase system. 

Conformational changes that occur on immobilization of a-lactalbumins on agarose cyclic imidocarbonate have been studied by fluorometric methods. Immobilized bovine a-lactalbumin has been employed in a study of acceptor-ligand interactions in the lactose synthase system. ... 

Lactose Synthases.—Lactose synthases and related systems have been reviewed. Affinity chromatography has been used in a quantitative study of acceptor-ligand interactions in the lactose synthase system. The effects of D-glucose and 2-acetamido-2-deoxy-D-glucose on the elution of the A-protein of human lactose synthase from a column of a-lactalbumin immobilized on agarose cyclic imidocarbonate gave values of 200 and 0.571 mol , respectively, for the association constants representing the interaction between the enzyme and the monosaccharides. 

The reactions of bovine a-lactalbumin with JV-bromosuccinimide and 2-hydroxy-5-nitrobenzyl bromide have led to a better understanding of the interaction of a-lactalbumin with the lactose synthase system and of the conformation of a-lactalbumin. Comparison of the properties of denatured forms of bovine a-lactalbumin and of hen egg-white lysozyme showed that different regions of the molecules unfold in response to denaturants. Amino-acid analyses confirmed that the compositions of the backbones of the two molecules are similar. 

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See also in sourсe #XX -- [ , ]

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