H⁺ exchange and pH profiling of select non-glycolytic cytosolic phosphate transfer and oxidation-reduction reactions

Despite animal research of cellular and systemic acidosis for more than 100 years, there is no dominant evidence-based understanding of the cause of metabolic acidosis. Embedded in this crisis state is the understanding that the hydrogen ion (H⁺) involved in some chemical reactions, either as a substrate or product (H⁺ exchange (H⁺ _e)), does not change the pH of biological solutions. This research documents the direct roles of the H⁺ _e of a selection of non-glycolytic cytosolic chemical reactions in changing the pH of an unbuffered aqueous solution.

Reagents were prepared using deionized water, substrates at known concentrations, enzymes and needed activator chemicals. The chemical reactions studied were creatine kinase (CKase) (to ATP and CrP), ATPase, hexokinase (HKase), and glucose-6-phosphate dehydrogenase (G₆PDHase). Each reaction was started by addition of the enzyme, and reagent pH was measured intermittently using a pH electrode. Samples of reagent (200 μL) were acquired for product measurement by spectrophotometry.

Results are presented as start pH:end pH; [Product], mmol·L^-1; pH:[Product] slope, pH.mmol^-1.L^-1: CKase to ATP (7.49:9.51; [1.95]; 1.289); CKase to CrP (8.29:7.89; [0.64]; -1.35); ATPase (8.94:8.23; [0.84]; -0.9385); HKase (8.59:6.55; [2.36];-1.596), G₆PDHase (7.53:6.89; [1.46]; -0.8006). All chemical reactions that produced carboxylic acids did so as anions, and all resulted in pH responses consistent with the role of the H⁺ as a substrate or product. The sequencing or summing of the CKase, ATPase, HKase and G6PDHase reactions revealed potential for summative computational modelling.

The evidence opposes traditional theories as the sole cause of cellular or systemic acidosis.