Riboflavin 5'-sulfate is a derivative of riboflavin conjugated with a sulfate group at the terminal end of the ribityl moiety. Riboflavin 5' and 3' sulfate have been observed to accumulate in the roots of iron-deficient sugar beets.

Pyridoxine-phosphate is a vitamer of Vitamin B6. In man vitamin B(6) ingested from the diet exists as six different vitamers, pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), pyridoxal 5'-phosphate (PLP), pyridoxamine 5'- phosphate (PMP) and pyridoxine 5'-phosphate (PNP). It is a substrate for pyridoxine-5'-phosphate oxidase (PNPO) and pyridoxal phosphate phosphatase (PDXP). PNPO deficiency is responsible of severe neonatal encephalopathy.