ION SERIES AND THE PHYSICAL PROPERTIES OF PROTEINS. I.

Area of Science:

• Biochemistry
• Physical Chemistry

Background:

• Investigating the physical properties of protein solutions is crucial for understanding their behavior in various applications.
• Previous studies often compared acids and alkalies based on concentration, leading to varied results.

Purpose of the Study:

• To determine the influence of acids and alkalies on the osmotic pressure and viscosity of egg albumin and gelatin solutions.
• To clarify the role of pH and ion valence in protein-acid/alkali interactions.

Main Methods:

• Experiments were conducted on crystalline egg albumin and gelatin solutions.
• Osmotic pressure and viscosity were measured under controlled pH and protein concentration.
• Different acids (monovalent and dibasic) and alkalies (monovalent and divalent cations) were used.

Main Results:

• Acid and alkali effects on protein solutions are dependent on pH and ion valence, not solely on the type of ion.
• Monovalent anions and cations showed consistent effects at the same pH.
• Dibasic acids (like H(2)SO(4)) and divalent cations (like Ca(2+), Ba(2+)) resulted in approximately half the osmotic pressure and viscosity compared to monovalent counterparts at equivalent pH.

Conclusions:

• The valence of ions, particularly in salt formation with proteins, significantly impacts solution properties.
• Controlling pH is critical for reproducible studies on protein-acid/alkali interactions.
• Results challenge previous ion-series-based interpretations, emphasizing the importance of pH-dependent interactions.