Arginine dipeptides affect insulin aggregation in a pH- and ionic strength-dependent manner.

Area of Science:

• Biochemistry
• Pharmaceutical Sciences
• Protein Chemistry

Background:

• Arginine and amino acid mixtures are vital for stabilizing protein liquid formulations.
• Challenges include high viscosities, aggregation, and phase separation in protein solutions.
• Improving arginine's stabilizing efficacy is crucial for advanced drug delivery.

Purpose of the Study:

• To investigate if incorporating arginine into dipeptides enhances its protein stabilizing properties.
• To evaluate the efficacy of arginine-containing dipeptides in suppressing insulin aggregation.
• To elucidate the molecular mechanisms behind dipeptide stabilization of proteins.

Main Methods:

• Tested arginine-containing dipeptides for their ability to suppress insulin aggregation.
• Utilized turbidimetry and light scattering at room temperature (pH 5.5, 3.7).
• Measured thermal-induced aggregation at pH 7.5 and quantified additive binding via intrinsic fluorescence.

Main Results:

• The dipeptide diArg demonstrated superior performance in suppressing insulin aggregation at pH 5.5 and 3.7.
• The dipeptide Arg-Phe effectively prevented thermal-induced insulin aggregation up to 90°C at pH 7.5.
• Established a molecular basis for how dipeptides influence insulin aggregation.

Conclusions:

• Arginine-containing dipeptides offer enhanced stabilization for protein formulations compared to arginine alone.
• Specific dipeptides provide potent suppression of insulin aggregation under diverse conditions.
• This research provides a foundation for developing novel protein stabilization strategies using peptide-based additives.