Bioengineering of photosynthetic membranes. Requirement of magnesium for the conversion of chlorophyllide a to chlorophyll a during the greening of etiochloroplasts in vitro

Journal Article · Sun Jan 01 00:00:00 EST 1984 · Biotechnol. Bioeng.; (United States)

DOI:https://doi.org/10.1002/bit.260260512· OSTI ID:6546973

Daniell, H; Rebeiz, C A

The massive conversion of delta-aminolevulinic acid (ALA) to protochlorophyllide (Pchlide) and the massive conversion of chlorophyllide a (Chlide a) to chlorophyll a (Chl a) are two essential conditions for the ALA-dependent assembly of photosynthetic membranes in vitro. In this work, the authors describe the development of a cell-free system capable of the forementioned biosynthetic activities at rates higher than in vivo, for the first 2 h of dark-incubation. The cell-free system consisted of 1) etiochloroplasts prepared from kinetin and gibberellic-acid-pretreated cucumber cotyledons, and 2) cofactors and additives described elsewhere and which are needed for the massive conversion of ALA to Pchlide, 3) high concentrations of ATP, MgCl/sub 2/, and an isoprenol alcohol such as phytol, were required for the massive conversion of Chlide a to Chl a. An absolute and novel requirement of Mg/sup 2 +/ for the conversion of Chlide a to Chl a was also demonstrated. In addition to the role of phytol as a substrate for the conversion of Chlide a to Chl a, the data suggested that this alcohol may also be involved in the regulation of the reactions between ALA and Pchlide. It is proposed that during greening, the conversion of Chlide a to Chl a may follow different biosynthetic rates, having different substrate and cofactor requirements, depending on the stage of plastid development.

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 6546973
• Journal Information: Biotechnol. Bioeng.; (United States), Vol. 26:5
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
CHLOROPHYLL
BIOCONVERSION
BIOMIMETIC PROCESSES
MAGNESIUM
USES
PHOTOSYNTHETIC MEMBRANES
CHEMICAL PREPARATION
AMINOLEVULINIC ACID
CUCUMBERS
IN VITRO
KINETIN
SEEDS
ADENINES
ALKALINE EARTH METALS
AMINES
AMINO ACIDS
ANTIMETABOLITES
AROMATICS
AZAARENES
CARBOXYLIC ACIDS
DRUGS
ELEMENTS
FOOD
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MEMBRANES
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
PURINES
SYNTHESIS
VEGETABLES
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)