Grafting of Aliphatic and Aromatic Probes on Bovine Serum Albumin: Influence on Its Structural and Physicochemical Characteristics

Abstract

Bovine serum albumin was chosen as a model protein to study the effect of the functionalization of the epsilon-NH2 of lysine residues with different carbon chains on the physical properties of proteins. Thus, BSA has been acylated and sulfonylated by means of anhydrides and sulfonyl chlorides, respectively. The secondary structures of modified BSA, studied by far-UV CD, showed very slight changes except after sulfamidation. However, near-UV CD and intrinsic fluorescence spectra revealed important conformational perturbations for proteins bearing long carbon chains. Furthermore, the binding of an apolar probe (ANS) to BSA revealed an improvement of surface hydrophobicity after modification. Meanwhile, Scatchard plot results indicate that only 20% of the hexanoyl carbon chains lie at the surface of the proteins. Solvent conditions should influence the exposure of these chains and consequently the surface hydrophobicity of proteins.

Foaming Properties of Acylated Rapeseed (Brassica napus L.) Hydrolysates

“…To minimize this problem, an excess of acid derivative is generally used (18). Thus, different ratios of rapeseed hydrolysate and acyl chloride were tested to find the best balance between the amount of reagent used and the degree of modification reached (Table 1).…”

“…It can be observed that the degree of modification increased from C 6 to C 10 acyl chlorides and then decreased. These different percentages of acylation are related to their different reactivity and stability in aqueous media (18). Final freeze-dried acylated hydrolysates had a peptide content that ranged from 42 to 48%.…”

Association Mechanism and Conformational Changes in Trypsin on Its Interaction with Atrazine: A Multi- Spectroscopic and Biochemical Study with Computational Approach

“…The k q for the TYP-ATR system at different temperatures is presented in Table 1 . The values of k q were found higher than the value of the collision quenching constant (2 × 10 10 M −1 s −1 ), suggestive of a static quenching mechanism in the TYP-ATR system [ 41 , 42 ].…”

Casein‐based conjugates and graft copolymers. Synthesis, properties, and applications

“…The carboxylic acids are beforehand activated in the form of anhydride and the most frequently used are acetic anhydride and even more succinic anhydride. Generally, acylation is performed at room temperature by adding the anhydride (1–3 equivalents per lysine group) dropwise to the protein solution, at pH ≅ 9 to keep amines in non‐protonated form (Gerbanowski et al., 1999).…”

“…The carboxylic acids are beforehand activated in the form of anhydride and the most frequently used are acetic anhydride and even more succinic anhydride. Generally, acylation is performed at room temperature by adding the anhydride (1-3 equivalents per lysine group) dropwise to the protein solution, at pH ≅ 9 to keep amines in non-protonated form (Gerbanowski et al, 1999). Succinylation of food proteins is listed in a recent review where the properties of water solubility, emulsification, foaming, thermal stability, rheology, nutrition, encapsulation, and drug release are highlighted (Basak & Singhal, 2022).…”