May 20, 2019, 04:57:59 PM
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Topic: Structural formula for beta-glucan assay method (Megazyme)  (Read 96 times)

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Offline lken

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I am preparing a lab experiment to find the beta-glucan content of mushroom extracts via colourmetric method. I have limited organic chemistry experience, but have a biology background and would love to understand the science behind what I am doing. I would like to create a the structural formula for the reactions that will take place in my experiment. I am curious to understand the molecular geometry - how the electrons are moving and breaking up bonds. I want to draw it all out and post it in my lab - but I really have no idea where to start and how to determine the molecular structures I am working it - I think if I saw them I might have an idea of where the electrons are moving and why they are reacting in certain ways. I have pasted a link below, and the general principal of the method from the megazyme website. Are there resources a novice chemical can tap into to help with this sort of thing? I'm probably being naive, but something like a database of structures that I can search through? If I have an idea of the structures I am working with, I can do some work by myself and then ask questions here one step at a time to see if I have the reactions right.

Thank you,

(1) β-Glucan + H2O → β-gluco-oligosaccharides
(2) β-Gluco-oligosaccharides + H2O → D-glucose
                               (glucose oxidase)
(3) D-Glucose + H2O + O2 → D-gluconate + H2O2
(4) 2H2O2 + p-hydroxybenzoic acid + 4-aminoantipyrine →   quinoneimine + 4H2O

Offline Babcock_Hall

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Re: Structural formula for beta-glucan assay method (Megazyme)
« Reply #1 on: May 10, 2019, 04:48:45 PM »
I am not aware of a single repository of chemical structures, but many are found by simply searching the web.  The structures of carbohydrates such as glucose can be represented in more than one way.  I think that you should use Haworth representations, as a good compromise between realism and ease of drawing.  For exam the Haworth projection of glucose is shown here:

Many times when one write a structure, one does not indicate the carbon atoms explicitly.  Instead they are understood to be at the vertices of angles.  Also one often leaves the hydrogen atoms bound to these carbon atoms out of the drawing.  If one were to add them back, it is only a matter of using the Lewis octet rule.

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