Site of prenylation reaction in synthesis of phylloquinone (vitamin K1) by spinach chloroplasts.

1,4-Dihydroxy-2-naphthoate [1, 21 as the crucial intermediate in the biosynthesis of menaquinones in bacteria is formed from shikimate [3] via chorismate [2] and o-succinylbenzoate [I]. Prenylation [4] and methylation [I] result in formation of menaquinones of different length of side chain. The principal steps of the synthesis of the naphthoquinone moiety are similar for both plants and bacteria [5 71. In the present paper we wish to report on the prcnylation of 1,4-dihydroxy-2-naphthoate by phytyldiphosphate and subsequent methylation by S-adenosylmethionine to form phylloquinol in spinach chloroplasts. The site of the prenylation reaction is the chloroplast envelope membrane.