GLOSSARY

Transketolase transfers ketol carbon units between sugars using a thiamine coenzyme.

The cytosolic pentose-phosphate branch supplies NADPH and nucleotide-building sugars. Its oxidative phase differs from nonoxidative sugar rearrangement, and it is not a major direct ATP source. Cellular needs determine carbon redistribution. Ribose or reducing-carrier roles do not alone prove a supplement improves energy or performance. Distinguish precursor chemistry and pathway potential from human outcomes rather than assuming every nucleotide-related compound bypasses ordinary fueling or guarantees rapid ATP restoration.

Oxidized and reduced NAD forms support energy-related electron transfer; the phosphorylated pair supports many biosynthetic and reductive-defense reactions. Their pools and ratios are not fully interchangeable. Vitamin precursors contribute to coenzyme production, but extra intake without deficiency does not guarantee greater flux or performance. An external sample also does not fully represent mitochondrial redox conditions. Distinguish precursor supply, local coenzyme turnover and demonstrated benefit from supplementing a related compound.

For example, after training changes an enzyme result, first ask whether it was measured in blood, tissue or purified protein. Then assess assay conditions, nutrition and time since the last session alongside actual performance; this comparison helps distinguish a regulatory response from a nutritional deficiency or a presumed supplement need.