Unfolded protein molecules

Absorption of proteins in the 230-300 nm range is determined by the aromatic side chains of tyrosine (Xmax = 274 am), tryptophan (Xmax = 280 nm), and phenylalanine (Xmax = 257 nm). Because the difference in the absorption spectra of native and unfolded protein molecules is generally small, difference spectra can... 

Biopolymers e.g., polysaccharides, polynucleotides, unfolded protein molecules, that all attain expanded flexible structures in solution adsorb more or less according to the principles discussed above. 

Similar refolding experiments have been performed on many other proteins. In many cases, the native structure can be generated under suitable conditions. For other proteins, however, refolding does not proceed efficiently. In these cases, the unfolding protein molecules usually become tangled up with one another to form aggregates. Inside cells, proteins called chaperones block such illicit interactions (Sections 11.3.6). 

Figure 12. A protein foam, showing unfolded protein molecules at the air-water interface.

During the brief 5 s period, amide deuteriums in unfolded protein molecules are replaced with hydrogen faster than are amide deuteriums in... 

Does heat-induced aggregation involve in all cases unfolded protein molecules In Sec. II we saw that BSA and ovalbumin have a definite tendency to aggregate at room temperature this could be also the case for HSA [141] and RNase [161], since the heat stability of these proteins depends on concentration. Does this tendency increase with temperature below the temperature of incipient unfolding How could this aggregation process involving native species affect heat-induced unfolding ... 

As stressed many times in this chapter, analysis of the denaturation of globular proteins is a complex problem. In practice, what is generally monitored is the global result of two different processes the conformational transition of the molecule, and the subsequent aggregation of unfolded protein molecules in many cases, the two processes cannot be separated, and this is a first difficulty in the thermodynamical approach. The second level of problems is inherent to the processes themselves considered separately. 

FIG. 6 Distribution of partially unfolded protein molecule and protein hydrolysates at oil-water interface. 

---