Biosynthesis of digalactosyldiacylglycerol in plastids from 16:3 and 18:3 plants

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.93.4.1286· OSTI ID:5915216

Heemskerk, J W.M.; Heinz, E ^[1]; Storz, T; Schmidt, R R ^[2]

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1. Univ. of Hamburg (West Germany)
2. Univ. of Konstanz (West Germany)

Intact chloroplasts isolated from leaves of eight species of 16:3 and 18:3 plants and chromoplasts isolated from Narcissus pseudonarcissus L. flowers synthesize galactose-labeled mono-, di-, and trigalactosyldiacylglycerol (MGDG, DGDG, and TGDG) when incubated with UDP-(6-{sup 3}H)galactose. In all plastids, galactolipid synthesis, and especially synthesis of DGDG and TGDG, is reduced by treatment of the organelles with the nonpenetrating protease thermolysin. Envelope membranes isolated from thermolysin-treated chloroplasts of Spinacia oleracea L. (16:3 plant) and Pisum sativum L. (18:3 plant) or membranes isolated from thermolysin-treated chromoplasts are strongly reduced in galactolipid:galactolipid galactosyltransferase activity, but not with regard to UDP-Gal:diacylglycerol galactosyltransferase. For the intact plastids, this indicates that thermolysin treatment specifically blocks DGDG (and TGDG) synthesis, whereas MGDG synthesis is not affected. Neither in chloroplast nor in chromoplast membranes is DGDG synthesis stimulated by UDP-Gal. DGDG synthesis in S. oleracea chloroplasts is not stimulated by nucleoside 5{prime}-diphospho digalactosides. Therefore, galactolipid:galactolipid galactosyltransferase is so far the only detectable enzyme synthesizing DGDG.

• OSTI ID: 5915216
• Journal Information: Plant Physiology; (USA), Vol. 93:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
LIPIDS
BIOSYNTHESIS
PLANTS
PHYSIOLOGY
CHLOROPLASTS
LEAVES
PISUM
SPINACH
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS
CELL CONSTITUENTS
ENZYMES
FOOD
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
ORGANIC COMPOUNDS
SYNTHESIS
VEGETABLES
551001* - Physiological Systems- Tracer Techniques