Summary: Isoelectric focusing in thin-layer polyacrylamide gel has been applied successfully to the characterization and identification of calf rennet and its substitutes. The use of acidic pH gradients (pH range 2·5–6) allows the identification of calf and microbial rennets and bovine and pig pepsins.A new, very rapid and sensitive zymogram technique has been developed by overlaying the gel with a highly porous, transparent cellulose acetate film impregnated with casein.

The spread of respiratory allergies is increasing in parallel with the alarm of the scientific community. Evidently, our knowledge of the onset mechanisms of these diseases and, as a consequence, of the available remedies is inadequate. This review provides a brief, general description of current therapeutic resources and the state of research with regard to both drugs and medical devices in order to highlight their limits and the urgent need for progress. Increasing the amount of basic biochemical research will improve our knowledge of such onset mechanisms and the potential efficacy of therapeutic preparations.

Thirty-six years after the publication of the important article by Busa and Nuccitelli on the variability of intracellular pH (pH_i) and the interdependence of pH_i and intracellular Ca²⁺ concentration ([Ca²⁺]_i), little research has been carried out on pH_i and calcium signaling. Moreover, the results appear to be contradictory. Some authors claim that the increase in [Ca²⁺]_i is due to a reduction in pH_i, others that it is caused by an increase in pH_i. The reasons for these conflicting results have not yet been discussed and clarified in an exhaustive manner. The idea that variations in pH_i are insignificant, because cellular buffers quickly stabilize the pH_i, may be a limiting and fundamentally wrong concept. In fact, it has been shown that protons can move and react in the cell before they are neutralized. Variations in pH_i have a remarkable impact on [Ca²⁺]_i and hence on some of the basic biochemical mechanisms of calcium signaling. This paper focuses on the possible triggering role of protons during their short cellular cycle and it suggests a new hypothesis for an IP₃ proton dependent mechanism of action.

Inflammatory allergic and nonallergic respiratory disorders are spreading worldwide and often coexist. The root cause is not clear. This review demonstrates that, from a biochemical point of view, it is ascribable to protons (H⁺) released into cells by exogenous and endogenous acids. The hypothesis of acids as the common cause stems from two considerations: (a) it has long been known that exogenous acids present in air pollutants can induce the irritation of epithelial surfaces, particularly the airways, inflammation, and bronchospasm; (b) according to recent articles, endogenous acids, generated in cells by phospholipases, play a key role in the biochemical mechanisms of initiation and progression of allergic-type reactions. Therefore, the intracellular acidification and consequent Ca²⁺ increase, induced by protons generated by either acid pollutants or endogenous phospholipases, may constitute the basic mechanism of the multimorbidity of these disorders, and environmental acidity may contribute to their spread.

36 years after the publication of the important article by Busa and Nuccitelli on the variability of intracellular pH (pH_i) and the interdependence of pH_i and intracellular Ca²⁺ concentration ([Ca²⁺]_i), little research has been carried out on pH_i and calcium signaling. Moreover, the results appear to be contradictory. Some authors claim that the increase in [Ca²⁺]_i is due to a reduction in pH_i, others that it is caused by an increase in pH_i. The reasons for these conflicting results have not yet been discussed and clarified in an exhaustive manner. Variations in pH_i have a significant impact on the increase in [Ca²⁺]_i and hence on some of the basic biochemical mechanisms of calcium signaling. This paper focuses on the possible triggering role of protons, highlighting the mechanisms potentially involved and the open issues that could be clarified by research.