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Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
Strong ion reserve: a viewpoint on acid base equilibria and buffering
1Second Department of Intensive Care Medicine, "Georgios Papanikolaou" General Hospital of Thessaloniki, 57010, Exochi, Greece. m.agrafiotis@gmail.com
European Journal of Applied Physiology
|January 7, 2011
Summary
The body
Area of Science:
- Biochemistry
- Physiology
Background:
- Strong ions, like electrolytes, can bind to proteins.
- This binding is influenced by pH levels.
- These ions can be released to influence the body's acid-base balance.
Purpose of the Study:
- To explore the role of protein-bound strong ions in buffering acid-base disturbances.
- To define the concept of a 'strong ion reserve' within biological systems.
Main Methods:
- Literature review and theoretical analysis of acid-base physiology.
- Examination of the pH-dependent binding of strong ions to proteins.
Main Results:
- Strong ions reversibly bind to proteins in a pH-dependent manner.
- Recruitment of these ions from proteins can modulate the strong ion difference.
- This process acts as a buffer against acid-base disturbances, representing a 'strong ion reserve'.
Conclusions:
- Protein-bound strong ions play a significant physiological role in maintaining acid-base homeostasis.
- The 'strong ion reserve' is a crucial concept for understanding the body's buffering capacity.
Related Concept Videos
Acid/Base Strengths and Dissociation Constants
The relative strength of an acid or base is the extent to which it ionizes when dissolved in water. If the ionization reaction is essentially complete, the acid or base is termed strong; if relatively little ionization occurs, the acid or base is weak. There are many more weak acids and bases than strong ones. The most common strong acids and bases are listed below:
Buffer Systems in the Body
Chemical buffers play a critical role in the body's regulation of pH levels. These systems contain one or more compounds that stabilize pH changes by neutralizing strong acids or bases. When pH levels drop, hydrogen ions bind to a weak base; when pH levels rise, hydrogen ions are released. This dynamic process helps maintain pH within a narrow and stable range essential for normal physiological function.
A typical buffer system in bodily fluids includes a weak acid and its corresponding anion,...
A typical buffer system in bodily fluids includes a weak acid and its corresponding anion,...
Bicarbonate-Carbonic Acid Buffer
The carbonic acid-bicarbonate buffer system is critical for maintaining the body's pH balance. It operates on the equilibrium:
Acid-Base Balance
The human body maintains a narrow pH range regulated through acid-base balance. This balance is crucial as changes in the hydrogen ion concentration can disrupt cell membrane stability, alter protein structures, and change enzyme activities. The normal pH of arterial blood is 7.4, venous blood and interstitial fluid is 7.35, and intracellular fluid averages 7.0.
When the pH of arterial blood rises above 7.45, it results in a condition called alkalosis. Conversely, a drop below 7.35 leads to...
When the pH of arterial blood rises above 7.45, it results in a condition called alkalosis. Conversely, a drop below 7.35 leads to...
Buffers
A solution containing appreciable amounts of a weak conjugate acid-base pair is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added. A solution of acetic acid and sodium acetate is an example of a buffer that consists of a weak acid and its salt: CH3COOH (aq) + CH3COONa (aq). An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride: NH3 (aq) + NH4Cl...
Acid–Base Equilibria: Activity-Based Definition of pH
For an ideal solution, the pH is defined as the negative logarithm of the hydrogen ion concentration. For a non-ideal solution, an accurate measurement of the pH must consider the negative logarithm of the hydrogen ion activity rather than concentration. In such a solution, the pH can be more accurately defined as the negative logarithm of a product of the hydrogen ion concentration and its activity coefficient.
In solutions of very low ionic strength—for example, pure water—the activity...
In solutions of very low ionic strength—for example, pure water—the activity...

