Pantetheine and its corresponding disulfide pantethine play a key role in metabolism as building blocks of coenzyme A (CoA), an essential cofactor utilized in ∼4% of primary metabolism and central to fatty acid, polyketide, and nonribosomal peptide synthases. Using a combination of recombinant engineering and chemical synthesis, we show that the disulfide of <i>N</i>-pantoylglycyl-2-aminoethanethiol (GlyPan), with one fewer carbon than pantetheine, can rescue a mutant E. coli strain MG1655Δ<i>panC</i> lacking a functional pantothenate synthetase. Using mass spectrometry, we show that the GlyPan variant is accepted by the downstream CoA biosynthetic machinery, ultimately being incorporated into essential acyl carrier proteins. These findings...