A5012263604- Food composition and properties
- Microbial Metabolites in Food Biotechnology
- Phytase and its Applications
- Enzyme Production and Characterization
- Plant nutrient uptake and metabolism
- Cassava research and cyanide
- Polysaccharides and Plant Cell Walls
- Biofuel production and bioconversion
- Photosynthetic Processes and Mechanisms
- Plant responses to water stress
- Legume Nitrogen Fixing Symbiosis
- Polysaccharides Composition and Applications
- Aluminum toxicity and tolerance in plants and animals
- Glycogen Storage Diseases and Myoclonus
- Lipid metabolism and biosynthesis
- Proteins in Food Systems
- Enzyme Catalysis and Immobilization
- Plant Stress Responses and Tolerance
- Diet and metabolism studies
- Yeasts and Rust Fungi Studies
- Botanical Research and Applications
- Crystallization and Solubility Studies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Plant Micronutrient Interactions and Effects
- Plant Molecular Biology Research
University of Guelph
2015-2024
Imperial College London
2008
Plant Industry
2008
ACT Government
2008
Iowa State University
2008
University of Manchester
1992-2003
Bangor University
1992-1993
Protein phosphorylation in amyloplasts and chloroplasts of Triticum aestivum (wheat) was investigated after the incubation intact plastids with γ-32P-ATP. Among soluble phosphoproteins detected plastids, three forms starch branching enzyme (SBE) were phosphorylated (SBEI, SBEIIa, SBEIIb), both SBE (SBEI SBEIIa) shown to be sequencing immunoprecipitated 32P-labeled using quadrupole-orthogonal acceleration time flight mass spectrometry. Phosphoamino acid analysis indicated that proteins are...
Abstract Protein-protein interactions among enzymes of amylopectin biosynthesis were investigated in developing wheat (Triticum aestivum) endosperm. Physical between starch branching (SBEs) and synthases (SSs) identified from endosperm amyloplasts during the active phase deposition grain using immunoprecipitation cross-linking strategies. Coimmunoprecipitation experiments peptide-specific antibodies indicate that at least two distinct complexes exist containing SSI, SSIIa, either SBEIIa or...
Mutations affecting specific starch biosynthetic enzymes commonly have pleiotropic effects on other in the same metabolic pathway. Such genetic evidence indicates functional relationships between components of system, including synthases (SSs), branching (BEs), and debranching enzymes; however, molecular explanation for these interactions is not known. One possibility that SSs, BEs, and/or associate physically with each multisubunit complexes. To test this hypothesis, study sought to...
Abstract Starch is globally important as a source of food and, in addition, has wide range industrial applications. Much this agriculturally produced starch synthesized developing seeds, where its biological function to provide energy for seedling establishment. Storage seeds heterotrophic plastids called amyloplasts and distinct from the transient synthesis chloroplasts. This article reviews our current understanding storage biosynthesis occurring these organelles discusses recent advances...
High temperature during grain filling affects yield, starch amylose content and activity of biosynthesis enzymes in basmati rice. To investigate the physiological mechanisms underpinning effects high on rice grain, was grown under two conditions - 32 22 °C filling.High decreased period from to 26 days, reducing yield by 6%, caused a reduction total (3.1%) (22%). Measurable activities key involved sucrose conversion, synthase, ADP-glucose pyrophosphorylase, phosphorylase soluble synthase...
The amylose extender (ae–) mutant of maize lacks starch branching enzyme IIb (SBEIIb) activity, resulting in amylopectin with reduced branch point frequency, and longer glucan chains. Recent studies indicate isozymes soluble synthases form high molecular weight complexes SBEII isoforms. This study investigated the effect loss SBEIIb activity on interactions between biosynthetic enzymes endosperm amyloplasts. Results show distinct patterns protein–protein amyloplasts ae– mutants compared wild...
Amylopectin is a highly branched, organized cluster of glucose polymers, and the major component rice starch. Synthesis amylopectin requires fine co-ordination between elongation polymers by soluble starch synthases (SSs), generation branches branching enzymes (BEs), removal misplaced debranching (DBEs). Among various isozymes having role in biosynthesis, limited numbers SS BE have been demonstrated to interact via protein-protein interactions maize wheat amyloplasts. This study investigated...
amylose extender (ae−) starches characteristically have modified starch granule morphology resulting from amylopectin with reduced branch frequency and longer glucan chains in clusters, caused by the loss of activity major branching enzyme (SBE), which maize endosperm is SBEIIb. A recent study ae− lacking SBEIIb protein (termed ae1.1 herein) showed that novel protein–protein interactions between enzymes biosynthesis amyloplast could explain phenotype mutant. The present examined an allelic...
ABSTRACT In this study, the functional properties of A‐ and B‐type wheat starch granules from two commercial flours were investigated for digestibility in vitro, chemical composition (e.g., amylose, protein, ash content), gelatinization, retrogradation, pasting properties. The branch chain length distribution these also determined using high‐performance anion exchange chromatography (HPAEC). Wheat starches with different granular sizes not only had degrees enzymatic hydrolysis thermal...
The sugary-2 mutation in maize (Zea mays L.) is a result of the loss catalytic activity endosperm-specific SS (starch synthase) IIa isoform causing major alterations to amylopectin architecture. present study reports biochemical and molecular analysis an allelic variant expressing catalytically inactive form SSIIa sheds new light on its central role protein-protein interactions determination starch granule proteome. mutant revealed two amino acid substitutions, one being highly conserved...
The starch-rich endosperms of the Poaceae, which includes wild grasses and their domesticated descendents cereals, have provided humankind livestock with bulk daily calories since dawn civilization up to present day. There are currently unprecedented pressures on global food supplies, largely resulting from population growth, loss agricultural land that is linked increased urbanization, climate change. Since cereal yields essentially underpin world feed supply, it critical we understand...
The intracellular location of ADPglucose pyrophosphorylase (AGPase) in wheat during endosperm development was investigated by analysis the recovery marker enzymes from amyloplast preparations. Amyloplast preparations contained 20-28% total activity two plastidial and less than 0.8% cytosolic enzymes. Amylo plasts prepared at various stages development, 8-30 d post anthesis, between 2% 10% AGPase activity; this implies that 7% 40% is period development. Two proteins were recognized antibodies...
The many varied uses of starch in food and industrial applications often requires an understanding its physicochemical properties the detailed variations granule structure that underpin these properties. ability to manipulate storage structures depends on biosynthetic pathway, particular, how components pathway are coordinated regulated. This article presents a current overview known enzymes involved synthesis granule, with emphasis knowledge regulation cereals other crops may be applied...
Soluble sugars were extracted by low speed centrifugation from the apoplast of leaves barley (Hordeum distichum L.) infiltrated with water. Infection leaf brown rust fungus (Puccinia hordeii) resulted in a reduction concentration sucrose, glucose and fructose apoplast. Sugars present an apoplastic space occupying 12 17 cm3 m−2 area healthy infected tissue, respectively. Uptake hexoses intercellular hyphae is suggested as cause this reduction. The pH sap rust-infected was increased to 7·3 6·6...
Elevated proportions of amylose in cereals are commonly associated with either the loss starch branching or synthase activity. Goami 2 is a high-amylose mutant temperate japonica rice variety Ilpumbyeo. Genotyping revealed that and Ilpumbyeo carry same alleles for IIa granule-bound I genes. Analyses proteins SSI SSIIa accumulate inside mature granules 2, which similar to extender IR36ae. However, unlike mutants, SBEIIb was still detectable 2. Detection after protein fractionation most...