The denaturation of ribonuclease A, lysozyme alpha-lactalbumin, and myoglobin by urea, guanidine hydrochloride, and guanidine thiocyanate has been followed with the use of difference spectral measurements. The free energy of stabilization (delta GH2OD) has been determined by the linear extrapolation of the free energy of denaturation to zero denaturant concentration. The values of delta GH2OD a...

Cell-surface galactosyltransferase was studied in suspensions of intact baby hamster kidney fibroblasts with both endogenous and exogenous glycoprotein acceptors. The cell-surface location of galactosyltransferase was demonstrated in experiments with the enzyme modifier alpha-lactalbumin, which does not enter the cell. The addition of alpha-lactalbumin to the assay medium for galactosyltransfer...

Data obtained by the intrinsic protein fluorescence technique showed that, in addition to Ca2+ and Mg2+ ions, bovine alpha-lactalbumin also binds physiologically significant Na+ and K+ ions, the nucleotides ATP, ADP, UTP, UDP and UDP-galactose. The release of the bound Ca2+ ions from the protein in a medium modelling physiological conditions (containing Mg2+, Na+, K+, ATP and ADP in physiologic...

The ability of proteins to fold to well defined compact structures is one of the most remarkable examples of the effect of natural selection on biological molecules. To understand their properties, including the stability, the mechanism of folding, and the possibilities of misfolding and association, it is necessary to know the protein free energy landscape. We use NMR data as restraints in a M...

Of the 4 tyrosyl residues of bovine ar-lactalbumin, 2 were found to be quite reactive with N-acetylimidazole; the third group is less so, and the fourth is only weakly reactive. Acylation of the two most reactive groups results in a reversible increase in the quantum yield of a tryptophan residue or residues which emit maximally at 350 rnp. At relatively high concentrations of reagent, in addit...

Hsp16.5, isolated from the hyperthermophilic Archaea Methanococcus jannaschii, is a member of the small heat-shock protein family. Small Hsps have 12- to 42-kDa subunit sizes and have sequences that are conserved among all organisms. The recently determined crystal structure of Hsp16.5 indicates that it consists discretely of 24 identical subunits. Using fluorescence resonance energy transfer, ...

The transport of [14C]-radiolabelled beta-lactoglobulin and alpha-lactalbumin through Caco-2 cell monolayers grown on permeable filters was studied in order to evaluate the different protein pathways through the intestinal epithelium. beta-Lactoglobulin or alpha-lactalbumin (0.25-3 mg/ml) was introduced on the apical side of the monolayer and both the transport and the release of labelled mater...