Evidence for a nonstatistical carbon isotope distribution in natural glucose

• Published in: Plant physiology (Bethesda) Vol. 96; no. 2; pp. 609 - 614
• Main Authors: Rossmann, A. (Lehrstuhl fur Allgemeine Chemie und Biochemie TUM, Freising-Weihenstephan, Federal Republic of Germany), Butzenlechner, M, Schmidt, H.L
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.06.1991
• Subjects: ALMIDON; AMIDON; ANALISIS CUANTITATIVO; ANALYSE QUANTITATIVE; Analytical, structural and metabolic biochemistry; Atoms; BETA VULGARIS; Biological and medical sciences; Carbohydrates; Carbon dioxide; Carbon isotopes; CARBONE; CARBONO; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; Corn; Distillation; Ethanol; FERMENTACION; FERMENTATION; Fundamental and applied biological sciences. Psychology; GLUCOSA; GLUCOSE; ISOTOPE; Isotope effects; ISOTOPOS; Metabolism and Enzymology; METABOLISME; METABOLISMO; METABOLITE; METABOLITOS; Molecules; Oses; Other biological molecules; Plants; VIA BIOQUIMICA DEL METABOLISMO; VOIE BIOCHIMIQUE DU METABOLISME; ZEA MAYS; Biodegradation; Leuconostoc mesenteroides; Reaction product; Lactobacillus bulgaricus; Glucose; Radioisotope; Density distribution; Carbon; Fungi; Streptococcaceae; Content; Bacteria; Lactobacillaceae; Micrococcales; Ascomycetes; Saccharomyces cerevisiae; Comparative study; Thallophyta
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.96.2.609

The relative carbon isotope content (delta 13C value) in each position of glucose from a C4 plant (maize starch) and a C3 plant (sugar beet sucrose) has been determined by stepwise chemical and biochemical degradation of the molecule and stable isotope ratio measurement of the fragments. The suitability of the degradation methods has been tested through their chemical yield and isotope balance. The results from both methods agreed perfectly, revealing a defined and reproducible 13C distribution in glucose from both origins. Most prominent was a relative 13C enrichment by 5 to 6 delta-units in position 4 and a depletion by about 5 delta-units in carbon 6. As possible reasons for these nonstatistical isotope distributions, isotope effects of the aldolase, the triose phosphate isomerase, and the transketolase reactions during carbohydrate biosynthesis are discussed. The practical importance of the results in regard to isotope distributions in secondary plant products as a means for food authenticity control is outlined