zwierzęta: Glucose

Evidence: 100 • authority: 72

Glucose is a sugar with the molecular formula C6H12O6. It is the most abundant monosaccharide, a subcategory of carbohydrates. It is made from water and carbon dioxide during photosynthesis by plants and most algae. It is used by plants to make cellulose, the most abundant carbohydrate in the world, for use in cell walls, and by all living organisms to make adenosine triphosphate (ATP), which is used by the cell as energy. Glucose is often abbreviated as Glc. In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is stored as a polymer, in plants mainly as amylose and amylopectin, and in animals as glycogen. Glucose circulates in the bl…

Evidence: 45 • authority: 92

Three Water Molecules Mediate Ring Opening of d‑Glucose in Aqueous Solutions.. The mechanism of d-glucose ring opening has long been debated, particularly with regard to whether proton transfer occurs through a concerted or stepwise pathway and how many water molecules participate in the process. Here, we employ ab initio molecular dynamics combined with metadynamics to investigate both possibilities. Our results identify a lower-energy concerted pathway in which proton transfer is mediated by a three-water hydrogen-bond network. Indeed, the transition state features a cyclic hydrogen-bonded water bridge linking OH 1 and O 5 . This bridge promotes proton transfer from OH 1 to O 5 , thereby…

Evidence: 45 • authority: 72

In chemistry, a substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. If a mixture is separated to isolate one chemical substance to a desired degree, the resulting substance is said to be chemically pure. Chemical substances can exist in several different physical states or phases (e.g. solids, liquids, gases, or plasma) without changing their chemical composition. Substances transition between these phases of matter in response to changes in temperature or pre…

Evidence: — • authority: 88

The crystal structure of rabbit phosphoglucose isomerase complexed with D‐sorbitol‐6‐phosphate, an analog of the open chain form of D‐glucose‐6‐phosphate. Abstract Phosphoglucose isomerase (PGI) catalyzes the isomerization of D‐glucose‐6‐phosphate (G6P) and D‐fructose‐6‐phosphate (F6P) in glycolysis and gluconeogenesis. Analysis of previously reported X‐ray crystal structures of PGI without ligand, with the cyclic form of F6P, or with inhibitors that mimic the cis ‐enediol intermediate led to proposed mechanisms for the ring opening and isomerization steps in the multistep catalytic mechanism. To help complete our model of the overall mechanism, information is needed about the state of PGI…

Evidence: — • authority: 72

A reducing sugar is any sugar that is capable of acting as a reducing agent. In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent, for example in Benedict's reagent. In such a reaction, the sugar becomes a carboxylic acid. All monosaccharides are reducing sugars, along with some disaccharides, some oligosaccharides, and some polysaccharides. The monosaccharides can be divided into two groups: the aldoses, which have an aldehyde group, and the ketoses, which have a ketone group. Ketoses must first tautomerize to aldoses before they can act as reducing sugars. The common dietary monosaccharides galactose, glucose and fructose are…

Evidence: — • authority: 72

l-Glucose is an organic compound with formula C6H12O6 or O=CH[CH(OH)]5H, specifically one of the aldohexose monosaccharides. As the l-isomer of glucose, it is the enantiomer of the more common d-glucose. l-Glucose does not occur naturally in living organisms, but can be synthesized in the laboratory. l-Glucose is indistinguishable in taste from d-glucose, but cannot be used by living organisms as a source of energy because it cannot be phosphorylated by hexokinase, the first enzyme in the glycolysis pathway. One of the known exceptions is Trinickia caryophylli, a plant pathogenic bacterium, which contains the enzyme d-threo-aldose 1-dehydrogenase which is capable of oxidizing l-glucose. Lik…

Evidence: — • authority: 72

In chemistry, an open-chain compound (or open chain compound) or acyclic compound (Greek prefix α 'without' and κύκλος 'cycle') is a compound with a linear structure, rather than a cyclic one. An open-chain compound having no side groups is called a straight-chain compound (also spelled as straight chain compound). Many of the simple molecules of organic chemistry, such as the alkanes and alkenes, have both linear and ring isomers, that is, both acyclic and cyclic. For those with 4 or more carbons, the linear forms can have straight-chain or branched-chain isomers. The lowercase prefix n- denotes the straight-chain isomer; for example, n-butane is straight-chain butane, whereas i-butane is…

Evidence: — • authority: 92

A DFT-based Raman spectral atlas and vibrational assignment of aqueous glucose structures and derivatives.. Diabetes mellitus affects approximately 589 million adults worldwide, underscoring the need for accurate and noninvasive glucose monitoring to reduce complications. Although Raman spectroscopy shows promise for noninvasive blood glucose detection due to its molecular specificity and minimal interference, its application has been limited by the oversimplification of glucose as an open-chain structure in solution and unresolved assignments of characteristic bands-particularly the widely used 1125 cm⁻¹ peak. In this study, we combine density functional theory simulations with experimenta…