ABSTRACT
Another controlling factor is that the nanotubes can only be formed within a rather narrow ion concentration window. These -lactalbumin nano-tubes have been found to consist of several hydrolysis products with molar mass ranging from 10 to 14 kDa. This mixture of hydrolysis products self-assembles into helical structures via a nucleation and growth mechanism. The minimum protein concentration to form nanotubes of -lactalbumin is reported to be 20 g/l (50 C, 75 mM Tris buffer, pH 7.5, 2 mol Ca2+ per mol protein) (Graveland-Bikker and de Kruif, 2006). Below this protein concentration, fibrillar and/or random aggregates are obtained (Otte et al., 2005). Cross-linking with either transglutaminase or glutaraldehyde increases the stability of the -lactalbumin nanotubes (Graveland-Bikker and de Kruif, 2006).
