Fig. 1.

A simplified tocopherol and plastoquinone pathway in plants. DMPBQ 2,3-dimethyl-5-phytyl-1,4-benzoquinone, HGA homogentisic acid, HPP p-hydroxyphenylpyruvate, MPBQ 2-methyl-6-phytyl-1,4-benzoquinone, MSBQ 2-methyl-6-solanyl-1,4-benzoquinone. Enzymes are indicated by red colour: HPP dioxygenase (HPPD); homogentisatephytyltransferase (HPT); homogentisatesolanyltransferase (HST); MPBQ/MSBQ methyltransferase; Tocopherol cyclase (TC); and Tocopherol methyltransferase (TMT). Enzymes are marked with red font while substrates and products in black