Effects of glycine hydroxamate, carbon dioxide, and oxygen on photorespiratory carbon and nitrogen metabolism in spinach mesophyll cells

Journal Article · Fri Jan 01 04:00:00 EST 1982 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.69.5.1136· OSTI ID:5148766

Lawyer, A L; Cornwell, K L; Gee, S L; Bassham, J A

The effects of added glycine hydroxamate on the photosynthetic incorporation of /sup 14/CO/sub 2/ into metabolites by isolated mesophyll cells of spinach (Spinacia oleracea L.) was investigated under conditions favorable to photorespiratory (PR) metabolism (0.04% CO/sub 2/ and 20% O/sub 2/) and under conditions leading to nonphotorespiratory (NPR) metabolism (0.2% CO/sub 2/ and 2.7% O/sub 2/). Glycine hydroxamate (GH) is a competitive inhibitor of the photorespiratory conversion of glycine to serine, CO/sub 2/ and NH/sub 4//sup +/. During PR fixation, addition of the inhibitor increased glycine and decreased glutamine labeling. In contrast, labeling of glycine decreased under NPR conditions. This suggests that when the rate of glycolate synthesis is slow, the primary route of glycine synthesis is through serine rather than from glycolate. GH addition increased serine labeling under PR conditions but not under NPR conditions. This increase in serine labeling under PR conditions but not under NPR conditions. This increase in serine labeling at a time when glycine to serine conversion is partially blocked by the inhibitor may be due to serine accumulation via the ''reverse'' flow of photorespiraton from 3-P-glycerate to hydroxypyruvate when glycine levels are high. GH increased glyoxylate and decreased glycolate labeling. These observations are discussed with respect to possible glyoxylate feedback inhibition of photorespiration.

• Research Organization: Univ. of California, Berkeley
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5148766
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 69; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550301 -- Cytology-- Tracer Techniques
551001 -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
AMINO ACIDS
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
FOOD
HYDROXAMIC ACIDS
HYDROXY COMPOUNDS
INHIBITION
LABELLED COMPOUNDS
METABOLISM
NITROGEN
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANT CELLS
RESPIRATION
SPINACH
SYNTHESIS
VEGETABLES