Vitamin B5 (pantothenate) metabolism

Vitamin B5 ((R)-pantothenate, PanK), is an essential precursor for the synthesis of the metabolic cofactor Coenzyme A (CoA-SH) and is the prosthetic group of acyl carrier protein (ACP). The name pantothenate is from the Greek “pantothen”, "from everywhere". Both pantothenate and CoA-SH are found in nearly every foodstuff and in the gut microbiome. CoA-SH itself is readily degraded in the gut and in extracellular fluids within the body. No processes are known to transport it across plasma membranes. Instead, individual cells take up PanK, which is stable in the extracellular environment, to synthesize CoA-SH for their own use. Within a cell, distinct groups of CoA-SH-requiring reactions occur in the cytosol, mitochondrial matrix, and peroxisomes, and controlling CoA pool size in each location plays a major role in regulating and integrating cellular metabolic processes. Control is achieved by selective degradation, synthesis, and transport of CoA within a cell. The reactions annotated here provide an incomplete description of these processes, as key steps remain incompletely understood.

Summary from Reactome (R-HSA-199220), read 2026-09-23.