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Nature Communications Aug 2022The gut microbiome is an important determinant in various diseases. Here we perform a cross-sectional study of Japanese adults and identify the Blautia genus, especially...
The gut microbiome is an important determinant in various diseases. Here we perform a cross-sectional study of Japanese adults and identify the Blautia genus, especially B. wexlerae, as a commensal bacterium that is inversely correlated with obesity and type 2 diabetes mellitus. Oral administration of B. wexlerae to mice induce metabolic changes and anti-inflammatory effects that decrease both high-fat diet-induced obesity and diabetes. The beneficial effects of B. wexlerae are correlated with unique amino-acid metabolism to produce S-adenosylmethionine, acetylcholine, and L-ornithine and carbohydrate metabolism resulting in the accumulation of amylopectin and production of succinate, lactate, and acetate, with simultaneous modification of the gut bacterial composition. These findings reveal unique regulatory pathways of host and microbial metabolism that may provide novel strategies in preventive and therapeutic approaches for metabolic disorders.
Topics: Acetylcholine; Administration, Oral; Adult; Amylopectin; Animals; Carbohydrate Metabolism; Clostridiales; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diet, High-Fat; Gastrointestinal Microbiome; Humans; Japan; Mice; Mice, Inbred C57BL; Obesity; Ornithine; Symbiosis
PubMed: 35982037
DOI: 10.1038/s41467-022-32015-7 -
The New Phytologist Dec 2020Starch granules are composed of two distinct glucose polymers - amylose and amylopectin. Amylose constitutes 5-35% of most natural starches and has a major influence... (Review)
Review
Starch granules are composed of two distinct glucose polymers - amylose and amylopectin. Amylose constitutes 5-35% of most natural starches and has a major influence over starch properties in foods. Its synthesis and storage occurs within the semicrystalline amylopectin matrix of starch granules, this poses a great challenge for biochemical and structural analyses. However, the last two decades have seen vast progress in understanding amylose synthesis, including new insights into the action of GRANULE BOUND STARCH SYNTHASE (GBSS), the major glucosyltransferase that synthesises amylose, and the discovery of PROTEIN TARGETING TO STARCH1 (PTST1) that targets GBSS to starch granules. Advances in analytical techniques have resolved the fine structure of amylose, raising new questions on how structure is determined during biosynthesis. Furthermore, the discovery of wild plants that do not produce amylose revives a long-standing question of why starch granules contain amylose, rather than amylopectin alone. Overall, these findings contribute towards a full understanding of amylose biosynthesis, structure and function that will be essential for future approaches to improve starch quality in crops.
Topics: Amylopectin; Amylose; Glucans; Starch; Starch Synthase
PubMed: 32767769
DOI: 10.1111/nph.16858 -
The Journal of Biological Chemistry Jun 2022Not all starches in the human diet are created equal: "resistant starches" are consolidated aggregates of the α-glucan polysaccharides amylose and amylopectin, which...
Not all starches in the human diet are created equal: "resistant starches" are consolidated aggregates of the α-glucan polysaccharides amylose and amylopectin, which escape digestion by salivary and pancreatic amylases. Upon reaching the large intestine, resistant starches become fodder for members of the human gut microbiota, impacting the metabolism of both the symbionts and the host. In a recent study, Koropatkin et al. provided new molecular insight into how a keystone bacterium in the human gut microbiota adheres to resistant starches as a prelude to their breakdown and fermentation.
Topics: Amylopectin; Amylose; Gastrointestinal Microbiome; Glucans; Humans; Starch; alpha-Amylases
PubMed: 35597281
DOI: 10.1016/j.jbc.2022.102049 -
Cellular and Molecular Life Sciences :... Jul 2016During starch metabolism, the phosphorylation of glucosyl residues of starch, to be more precise of amylopectin, is a repeatedly observed process. This phosphorylation... (Review)
Review
During starch metabolism, the phosphorylation of glucosyl residues of starch, to be more precise of amylopectin, is a repeatedly observed process. This phosphorylation is mediated by dikinases, the glucan, water dikinase (GWD) and the phosphoglucan, water dikinase (PWD). The starch-related dikinases utilize ATP as dual phosphate donor transferring the terminal γ-phosphate group to water and the β-phosphate group selectively to either C6 position or C3 position of a glucosyl residue within amylopectin. By the collaborative action of both enzymes, the initiation of a transition of α-glucans from highly ordered, water-insoluble state to a less order state is realized and thus the initial process of starch degradation. Consequently, mutants lacking either GWD or PWD reveal a starch excess phenotype as well as growth retardation. In this review, we focus on the increased knowledge collected over the last years related to enzymatic properties, the precise definition of the substrates, the physiological implications, and discuss ongoing questions.
Topics: Arabidopsis; Phenotype; Phosphates; Phosphorylation; Starch; Substrate Specificity
PubMed: 27147464
DOI: 10.1007/s00018-016-2248-4 -
Carbohydrate Polymers Mar 2013Starch is an agricultural raw material used in many food and industrial products. It is present in granules that vary in shape in the form of amylose and amylopectin.... (Review)
Review
Starch is an agricultural raw material used in many food and industrial products. It is present in granules that vary in shape in the form of amylose and amylopectin. Starch-degrading enzymes are used on a large scale in the production of sweeteners (high fructose corn syrup) and concentrated glucose syrups as substrate for the fermentative production of bioethanol and basic chemicals. Over the last two decades α-glucanotransferases (EC 2.4.1.xx), such as branching enzyme (EC 2.4.1.18) and 4-α-glucanotransferase (EC 2.4.1.25), have received considerable attention. These enzymes do not hydrolyze the starch as amylases do. Instead, α-glucanotransferases remodel parts of the amylose and amylopectin molecules by cleaving and reforming α-1,4- and α-1,6-glycosidic bond. Here we review the properties of α-glucanotransferases and discuss the emerging use of these enzymes in the generation of novel starch derivatives.
Topics: 1,4-alpha-Glucan Branching Enzyme; Amylopectin; Amylose; Bacteria; Bacterial Proteins; Biocatalysis; Food Industry; Glucosyltransferases; Glycogen Debranching Enzyme System; Hydrolysis; Molecular Conformation; Molecular Weight; Time Factors
PubMed: 23465909
DOI: 10.1016/j.carbpol.2012.01.065 -
Annual Review of Food Science and... Mar 2023Starch is one of the most abundant renewable biopolymers in nature and is the main constituent in the human diet and a raw material for the food industry. Native... (Review)
Review
Starch is one of the most abundant renewable biopolymers in nature and is the main constituent in the human diet and a raw material for the food industry. Native starches are limited in most industrial applications and often tailored by structural modification to enhance desirable attributes, minimize undesirable attributes, or create new attributes. Enzymatic approaches for structuring starch have become of interest to the food industry precisely because the reactions minimize the formation of undesirable by-products and coproducts and are therefore considered environmentally friendly methods for producing clean-label starches with better behavioral characteristics. Starches with improved functionalities for various applications are produced via enzyme hydrolysis and transfer reactions. Use of novel, multifunctional, starch-active enzymes to alter the structures of amylose and/or amylopectin molecules, and thus alter the starch's physiochemical attributes in a predictable and controllable manner, has been explored. This review provides state-of-the-art information on exploiting glycosyl transferases and glycosyl hydrolases for structuring starch to improve its functionalities. The characteristics of starch-active enzymes (including branching enzymes, amylomaltases, GH70 α-transglycosylases, amylosucrases, maltogenic amylases, cyclomaltodextrinases, neopullulanases, and maltooligosaccharide-forming amylases), structure-functionality-driven processing strategies, novel conversion products, and potential industrial applications are discussed.
Topics: Humans; Starch; Amylopectin; Amylose; Amylases; Hydrolysis
PubMed: 36525688
DOI: 10.1146/annurev-food-072122-023510 -
Cellular and Molecular Life Sciences :... Jul 2016Starch-rich crops form the basis of our nutrition, but plants have still to yield all their secrets as to how they make this vital substance. Great progress has been... (Review)
Review
Starch-rich crops form the basis of our nutrition, but plants have still to yield all their secrets as to how they make this vital substance. Great progress has been made by studying both crop and model systems, and we approach the point of knowing the enzymatic machinery responsible for creating the massive, insoluble starch granules found in plant tissues. Here, we summarize our current understanding of these biosynthetic enzymes, highlighting recent progress in elucidating their specific functions. Yet, in many ways we have only scratched the surface: much uncertainty remains about how these components function together and are controlled. We flag-up recent observations suggesting a significant degree of flexibility during the synthesis of starch and that previously unsuspected non-enzymatic proteins may have a role. We conclude that starch research is not yet a mature subject and that novel experimental and theoretical approaches will be important to advance the field.
Topics: Enzymes; Phosphorylation; Plant Cells; Starch; Substrate Specificity
PubMed: 27166931
DOI: 10.1007/s00018-016-2250-x -
Vavilovskii Zhurnal Genetiki I Selektsii May 2022Starch is a major storage carbohydrate in plants. It is an important source of calories in the human and animal diet. Also, it is widely used in various industries....
Starch is a major storage carbohydrate in plants. It is an important source of calories in the human and animal diet. Also, it is widely used in various industries. Native starch consists of water-insoluble semicrystalline granules formed by natural glucose polymers amylose and amylopectin. The physicochemical properties of starch are determined by the amylose:amylopectin ratio in the granule and degrees of their polymerization and phosphorylation. Potato Solanum tuberosum L. is one of the main starch-producing crops. Growing industrial needs necessitate the breeding of plant varieties with increased starch content and specified starch properties. This task demands detailed information on starch metabolism in the producing plant. It is a complex process, requiring the orchestrated work of many enzymes, transporter and targeting proteins, transcription factors, and other regulators. Two types of starch are recognized with regard to their biological functions. Transitory starch is synthesized in chloroplasts of photosynthetic organs and degraded in the absence of light, providing carbohydrates for cell needs. Storage starch is synthesized and stored in amyloplasts of storage organs: grains and tubers. The main enzymatic reactions of starch biosynthesis and degradation, as well as carbohydrate transport and metabolism, are well known in the case of transitory starch of the model plant Arabidopsis thaliana. Less is known about features of starch metabolism in storage organs, in particular, potato tubers. Several issues remain obscure: the roles of enzyme isoforms and different regulatory factors in tissues at various plant developmental stages and under different environmental conditions; alternative enzymatic processes; targeting and transport proteins. In this review, the key enzymatic reactions of plant carbohydrate metabolism, transitory and storage starch biosynthesis, and starch degradation are discussed, and features specific for potato are outlined. Attention is also paid to the known regulatory factors affecting starch metabolism.
PubMed: 35774362
DOI: 10.18699/VJGB-22-32 -
Bioengineered 2013Pullulanases are endo-acting enzymes capable of hydrolyzing α-1, 6-glycosidic linkages in starch, pullulan, amylopectin, and related oligosaccharides, while... (Review)
Review
Pullulanases are endo-acting enzymes capable of hydrolyzing α-1, 6-glycosidic linkages in starch, pullulan, amylopectin, and related oligosaccharides, while amylopullulanases are bifunctional enzymes with an active site capable of cleaving both α-1, 4 and α-1, 6 linkages in starch, amylose and other oligosaccharides, and α-1, 6 linkages in pullulan. The amylopullulanases are classified in GH13 and GH57 family enzymes based on the architecture of catalytic domain and number of conserved sequences. The enzymes with two active sites, one for the hydrolysis of α-1, 4- glycosidic bond and the other for α-1, 6-glycosidic bond, are called α-amylase-pullulanases, while amylopullulanases have only one active site for cleaving both α-1, 4- and α-1, 6-glycosidic bonds. The amylopullulanases produced by bacteria find applications in the starch and baking industries as a catalyst for one step starch liquefaction-saccharification for making various sugar syrups, as antistaling agent in bread and as a detergent additive.
Topics: Amino Acid Sequence; Amylopectin; Bacteria; Bacterial Proteins; Catalytic Domain; Conserved Sequence; Glucans; Glycoside Hydrolases; Molecular Sequence Data; Recombinant Proteins; Starch
PubMed: 23645215
DOI: 10.4161/bioe.24629 -
NPJ Science of Food Jun 2023The structure and properties of phytoglycogen and glycogen subjected to acid hydrolysis was investigated using amylopectin as a reference. The degradation took place in...
The structure and properties of phytoglycogen and glycogen subjected to acid hydrolysis was investigated using amylopectin as a reference. The degradation took place in two stages and the degree of hydrolysis was in the following order: amylopectin > phytoglycogen > glycogen. Upon acid hydrolysis, the molar mass distribution of phytoglycogen or glycogen gradually shifted to the smaller and broadening distribution region, whereas the distribution of amyopectin changed from bimodal to monomodal shape. The kinetic rate constant for depolymerization of phytoglycogen, amylopectin, and glycogen were 3.45 × 10/s, 6.13 × 10/s, and 0.96 × 10/s, respectively. The acid-treated sample had the smaller particle radius, lower percentage of α-1,6 linkage as well as higher rapidly digestible starch fractions. The depolymerization models were built to interpret the structural differences of glucose polymer during acid treatment, which would provide guideline to improve the structure understanding and precise application of branched glucan with desired properties.
PubMed: 37291152
DOI: 10.1038/s41538-023-00201-6