This is the present of asymmetric carbon atom in any compound. The present of asymmetric carbon atom in a compound give rise to formation of isomer of that compound, such will be identical in composition but differ in partial configuration; a compound of this nature is called sterio-isomers. Glucose exist as D-glucose and L-glucose, which is the carbohydrate isomer, see bellow the equation;
In a close look at fig 1.4, it will be found that there is a slightly change in H and OH groups around the carbon atom in the adjacent under the primary alcohol.
Glucose have six carbon atom arrange in series, the –OH attached to this carbon determine either the compound is L-series or D-series. When –OH is attached to the right carbon atom in the group chain, then the compound is said to be in D-series. But if the –OH is attached to the left side of the carbon atom chain in the group, then the compound is said to be in L-series.
In the broken down of any biological molecule, the reaction is been faster to a completion by a substance called enzymes. Enzyme is chemical substance responsible for metabolism in the body system. D-glucose is most of the monosaccharide found in mammalian systems, and they are the mostly enzyme that is responsible for the metabolism process in mammalian body.
In the practical aspect of determination of D and L-series of asymmetrical carbon atom an optical activity also is use on the compound, these happen by passing a beam of plane-polarized light through a solution given optical activity it will be found that the solution rotate to the left or right base on the status of the substance in question. When the solution rotate to the left, the compound is said to be L-series but if it rotate to right the compound is said to be D-series.
There is a tendency for specific amount of L-series and D-series of isomer result in one mixture, the dissolved optical activity, hence called Racemic why the separation of that optical activity isomer in the mixture is called resolution.
When two group of aldehyde and alcohol belong to the same class of molecule react together, this reaction result in the formation of cyclic structure in the compound in question, in this compound the open chain formed D-glucose called aldehyde
D-glucose, this aldehyde D-glucose is taken and dissolves the aldehyde carbon group one in the compound. With the attachment of alcoholic group –OH on the 5-carbon in the group, form two alike class of glucose, as the –OH group in the chain extends to the left β-D-Glucose is formed, but when it extend to the right, α-D-Glucose is formed, see equation bellow;
In the equation above, we can see that first carbon of the compound after the acyclation, it now have four different groups, in such case it render the compound asymmetrical in these, the two cyclic compound α- and β-D-glucose have different optical rotation actually they are not suppose to be the same, because the compound as a whole are not mirror-image of each other in this case are called anomer. But after the cyclation of carbon-one, the compounds now render asymmetric which is called anomeric carbon atom of the compound.
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