What type of metabolic pathway consists of enzyme-catalyzed reactions running in one direction?

A linear metabolic pathway is characterized by a series of enzyme-catalyzed reactions that proceed in a single direction, transforming a starting substrate into a final product through intermediates. This type of pathway is straightforward, with each reaction leading to the next without any branching off to create multiple products or reverting back to earlier stages.

In contrast, other pathways like circular metabolic pathways involve reactions that cycle back to the starting molecule, enabling continuous turnover, which is not the case in a linear pathway. Branched pathways allow for multiple endpoints from a common precursor, creating more complexity compared to the straightforward flow of a linear pathway. Convergent pathways involve multiple substrates contributing to a common product, which also adds to the complexity.

Thus, the defining characteristic of a linear metabolic pathway is its unidirectional flow of reactions leading directly from substrates to products without diversions.