Changes in the activities of carbon metabolizing enzymes with pod development in lentil (Lens culinaris L.)

Abstract

carbon metabolism, sucrose metabolism, sucrose synthase, sucrose phosphate synthase, invertase, phosphoenol pyruvate carboxylase, malic enzyme, isocitrate dehydrogenase. AbstractActivities of some key enzymes of carbon metabolism sucrose synthase, acid and alkaline invertase, phosphoenol pyrnvate carboxylase, malic enzyme and isocitrate dehydrogenase were investigated in relation to the carbohydrate status in lentil pods. Sucrose remained the dominant soluble sugar in the pod wall and seed, with hexoses (glucose and fructose) present at significantly lower levels. Sucrose synthase is the predominant sucrolytic enzyme in the developing seeds of lentil (Lens culinaris L.). Acid invertase was associated with pod elongation and showed little activity in seeds. Sucrose breakdown was dominated by alkaline invertase during the development of podwall, while both the sucrose synthase and alkaline invertase were active in the branch of inflorescence. A substantial increase of sucrolytic enzymes was observed at the time of maximum seed filling stage (10-20 DAF) in lentil seed. The pattern of activity of sucrose synthase highly paralleled the phase of rapid seed filling and therefore, can be correlated with seed sink strength. It seems likely that the fruiting structures of lentil utilize phosphoenol pyruvate carboxylase for recapturing respired carbon dioxide. Higher activities of isocitrate dehydrogenase and malic enzyme in the seed at the time of rapid seed filling could be effectively linked to the deposition of protein reserves.

Phytic acid and raffinose series oligosaccharides metabolism in developing chickpea seeds

“…Acid and alkaline phosphatases were extracted with 0.1 M sodium acetate buffer (pH 5.0) and 0.1 M Tris HCl buffer (pH 8.0) respectively (Kaur et al 1999). Acid and alkaline invertases were extracted with 0.02 M sodium phosphate buffer (pH 7.0) (Chopra et al 2003). Inorganic pyrophosphatase was extracted with 0.1 M Tris HCl buffer (pH 7.3) (Heppel 1955) and 3-phosphoglycerate phosphatase was extracted with 25 mM MES-KOH buffer (pH 6.0) (Villareal and Juliano 1977).…”

“…Activities of acid and alkaline invertases were determined by incubating 0.1 M sucrose in 0.1 M sodium acetate buffer pH 5.0 for acid invertase and 0.1 M sodium phosphate buffer pH 8.0 for alkaline invertase with 0.1 ml of enzyme extract in a total volume of 1 ml. Reducing sugars formed after sucrose hydrolysis were estimated (Chopra et al 2003). Acid and alkaline phytases were assayed using 2.2 mM sodium phytate in 0.05 M sodium acetate buffer pH 5.0 containing 1 mM CaCl 2 for acid phytase and in 0.1 M Tris HCl buffer pH 8.0 containing 1 mM CaCl 2 for alkaline phytase and enzyme extract of 0.1 ml in a total volume of 3.1 ml.…”

“…Free sugars were quantitatively extracted twice with 80 % ethanol, then twice with 70 % ethanol and contents of free fructose, sucrose, glucose were determined as described previously (Chopra et al 2003). Sucrose was determined by an enzymatic hydrolysis of the extract with acid invertase (Sigma) and then determining the glucose using glucose oxidase and peroxidase reaction (Chopra et al 2003).…”

“…Sucrose was determined by an enzymatic hydrolysis of the extract with acid invertase (Sigma) and then determining the glucose using glucose oxidase and peroxidase reaction (Chopra et al 2003). Raffinose and stachyose were separated on TLC silica gel G glass plates without fluorescent indicator (Eastman Kodak Company) by spotting known volume of carbohydrate extract using solvent system (butanol: isopropanol: water in 30: 120: 40 v/v/v).…”

Changes in the Activity of Carbon and Nitrogen Metabolising Enzymes in Nodules of Bold and Small Seeded Lentil Cultivars

“…Sucrose is the main carbohydrate transported through phloem to sink tissues like nodules, where it is metabolized by either sucrose synthase (SuSy) or alkaline invertase (AI) and the breakdown of sucrose into glucose and fructose, are essential proteins in plant life (Aleman et al, 2010;Mariana et al, 2013).The higher sucrose synthase activity observed in the nodules of bold seeded cultivars ensures hexose supply for meeting the energy and reducing power demands of nodules during the stage of active nitrogen fixation and probably may regulate carbon metabolism and nitrogen fixation (Chopra et al, 2003). In present investigation bold seeded cultivars showed higher status of PEP, MDH and IDH enzymes that indicate the utilization of glycolytic products for bacteroid respiration.…”