Partially carboxymethylated feather keratins. 1. Properties in aqueous systems

Area of Science:

• Biopolymer science
• Protein chemistry
• Materials science

Background:

• Feather keratin is a promising biopolymer for biodegradable materials.
• Extraction and purification of keratin often lead to protein aggregation.
• Controlling keratin's solubility and aggregation is crucial for material development.

Purpose of the Study:

• To develop stable keratin solutions/dispersions for biodegradable materials.
• To investigate the effect of cysteine modification on keratin aggregation.
• To balance the introduction of hydrophilic groups with the preservation of disulfide bonds for mechanical properties.

Main Methods:

• Extraction of feather keratin using urea and 2-mercaptoethanol.
• Partial modification of cysteine residues with iodoacetamide, iodoacetic acid, or bromosuccinic acid.
• Dialysis to remove reagents and analysis of protein aggregation and oligomerization.

Main Results:

• Partial modification of cysteine residues prevented extensive aggregation during dialysis.
• Higher degrees of cysteine modification led to fewer aggregates and more soluble oligomers.
• Reaction rate constants accurately predicted the degree of keratin cysteine modification.
• Intermolecular disulfide bonds stabilized the observed aggregates and oligomers.

Conclusions:

• Partial chemical modification of feather keratin cysteine residues yields stable solutions/dispersions.
• This approach allows for the development of biodegradable materials from keratin.
• Balancing modification and disulfide bond preservation is key for material properties.