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The main pathway of galactose metabolism is the Leloir pathway; humans and other species, however, have been noted to contain several alternate pathways, such as the De Ley Doudoroff Pathway. The Leloir pathway consists of the latter stage of a two-part process that converts β-D-galactose to UDP-glucose. The initial stage is the conversion of ...
The dispute is about: Unacceptable (confusing) structure diagram stereochemistry (bond angles) of bottom two structures (Please discuss here) Usage: {{disputed chem|reason}} You may want to notify the uploader(s) by placing the following code on their talk page {{subst:disputed chem/notification|D-Galactose Haworth.svg}}
Haworth projection of the structures for α-D-glucopyranose and α-L-glucopyranose. In chemistry, a Haworth projection is a common way of writing a structural formula to represent the cyclic structure of monosaccharides with a simple three-dimensional perspective.
From left to right: Haworth projections and ball-and-stick structures of the α- and β- anomers of D-glucopyranose (top row) and D-glucofuranose (bottom row) In solutions, the open-chain form of glucose (either " D -" or " L -") exists in equilibrium with several cyclic isomers , each containing a ring of carbons closed by one oxygen atom.
English: Structure of beta-D-galactopyranose (Haworth projection) Date: 16 March 2007: Source: Own work: ... Galactose; Galactose-1-phosphate uridylyltransferase ...
The stereochemical structure of a cyclic monosaccharide can be represented in a Haworth projection. In this diagram, the α-isomer for the pyranose form of a D -aldohexose has the −OH of the anomeric carbon below the plane of the carbon atoms, while the β-isomer has the −OH of the anomeric carbon above the plane.
Like the d-isomer, l-glucose usually occurs as one of four cyclic structural isomers—α- and β-l-glucopyranose (the most common, with a six-atom ring), and α- and β-l-glucofuranose (with a five-atom ring). In water solution, these isomers interconvert in matters of hours, with the open-chain form as an intermediate stage.
The aldohexose that is most important in biochemistry is D-glucose, which is the main "fuel" for metabolism in many living organisms. The 2-ketohexoses psicose, fructose and tagatose occur naturally as the D-isomers, whereas sorbose occurs naturally as the L-isomer. D-Sorbose is commonly used in the commercial synthesis of ascorbic acid. [10]