Introduction: While the evolutionary adaptation of enzymes to their own substrates is a well assessed and rationalized field, how molecules have been originally selected in order to initiate and assemble convenient metabolic pathways is a fascinating, but still debated argument.
Objectives: Aim of the present study is to give a rationale for the preferential selection of specific molecules to generate metabolic pathways.
Methods: The comparison of structural features of molecules, through an inductive methodological approach, offer a reading key to cautiously propose a determining factor for their metabolic recruitment.
Results: Starting with some commonplaces occurring in the structural representation of relevant carbohydrates, such as glucose, fructose and ribose, arguments are presented in associating stable structural determinants of these molecules and their peculiar occurrence in metabolic pathways.
Conclusions: Among other possible factors, the reliability of the structural asset of a molecule may be relevant or its selection among structurally and, a priori, functionally similar molecules.
Keywords: Carbohydrate metabolism; Enzyme selectivity; Hemiacetal stability; Metabolic steps genesis.