Tocopherol and plastoquinone synthesis in spinach chloroplasts subfractions.

Localization and synthesis of prenylquinones in isolated outer and inner envelope membranes from spinach chloroplasts.

The prenylquinone content and biosynthetic capabilities of membrane fractions enriched in outer and inner envelope membranes from spinach chloroplasts were analyzed. Both envelope membranes contain prenylquinones, and in almost similar amounts (on a protein basis). However, the outer envelope membrane contains more alpha-tocopherol than the inner one although this prenylquinone is the major one...

Biosynthesis of ubiquinone and plastoquinone in the endoplasmic reticulum-Golgi membranes of spinach leaves.

The localization of ubiquinone (UQ) and plastoquinone (PQ) biosynthesis in subfractions isolated from spinach leaves has been studied. UQ-9 and UQ-10 were found mainly in mitochondria, whereas PQ was enriched in chloroplasts, but also found in Golgi membranes. alpha-Unsaturated polyprenol-11 was also present at a low concentration in chloroplasts. Autoradiography revealed the presence of nonapr...

SITE OF BIOSYNTHESIS OF a-TOCOPHEROL IN SPINACH CHLOROPLASTS

The chloroplast envelope is a continuous boundary of two osmiophilic membranes and has an important role in galactolipid synthesis [ 11. It was interesting to determine whether the envelope is the site of synthesis of other lipid components in the chloroplast. We have chosen a-tocopherol for these experiments because it represents >40% of the total prenylquinones of the chloroplast [2]. The bio...

Comparison of geranylgeranyl and phytyl substituted methylquinols in the tocopherol synthesis of spinach chloroplasts.

Synthesis of prenylquinones in chioropiasts

In recent studies evidence was obtained that chioropiasts of higher plants possess an autonotnic system of isoprenoid synthesis. The prenyl moiety of the chloroplast isoprenoid compounds [i,e, carotenoids, chlorophylls, plastoquinones, tocopherols and phylloquinone (vitamin K,)] originates frotn geranyigeranyi-PP, The present review deals with some aspects of the fonnatioo of the plastidic pren...