Synthesis of glycolate from pyruvate via isocitrate lyase by tobacco leaves in light. [Nicotiana tabacum var Havana Seed]

Journal Article · Mon Feb 01 00:00:00 EST 1988 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.86.2.463· OSTI ID:7067158

Zelitch, I ^[1]

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1. Connecticut Agricultural Experiment Station, New Haven (USA)

Tobacco (Nicotiana tabacum var Havana Seed) leaf discs were supplied tracer quantities of (2-{sup 14}C)- and (3-{sup 14}C) pyruvate for 60 minutes in steady state photosynthesis with 21% or 1% O{sub 2}, and the glycolate oxidase inhibitor {alpha}-hydroxy-2-pyridinemethanesulfonic acid was then added for 5 or 10 minutes to cause glycolate to accumulate. The (3-{sup 14}C) pyruvate was converted directly to glycolate as shown by a 50% greater than equal-labeled {sup 14}C in C-2 of glycolate, and the fraction of {sup 14}C in C-2 increased in 1% O{sub 2} to 80% greater than equal-labeled. This suggests the pathway using pyruvate is less O{sub 2}-dependent than the oxygenase reaction producing glycolate from the Calvin cycle. The formation of glycolate from pyruvate in the leaf discs was time-dependent and with (2-{sup 14}C)- and (3-{sup 14}C) pyruvate supplied leaf discs the C-2 of glyoxylate derived from C-2 of isocitrate was labeled asymmetrically in a manner similar to the asymmetrical labeling of C-2 of glycolate under a number of conditions. Thus glycolate was probably formed by the reduction of glyoxylate. Isocitric lyase activity of tobacco leaves was associated with leaf mitochondria, through most of the activity was in the supernatant fraction after differential centrifugation of leaf homogenates.

• OSTI ID: 7067158
• Journal Information: Plant Physiology; (USA), Vol. 86:2; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GLYCOLIC ACID
BIOSYNTHESIS
NICOTIANA
PHOTOSYNTHESIS
BIOLOGICAL PATHWAYS
CARBON 14 COMPOUNDS
ENZYME ACTIVITY
INHIBITION
LEAVES
MITOCHONDRIA
OXIDOREDUCTASES
OXYGEN
PYRUVIC ACID
TIME DEPENDENCE
TRACER TECHNIQUES
VISIBLE RADIATION
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENZYMES
HYDROXY ACIDS
ISOTOPE APPLICATIONS
KETO ACIDS
LABELLED COMPOUNDS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MONOCARBOXYLIC ACIDS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PHOTOCHEMICAL REACTIONS
PLANTS
RADIATIONS
SYNTHESIS
550201* - Biochemistry- Tracer Techniques