TLS Online TPP Program

#Id: 7849

#Unit 1. Molecules and their Interaction Relevant to Biology

The pyranose form of glucose dominates (>99%) at equilibrium in aqueous solution

TLS Online TPP Program

#Id: 7850

#Unit 1. Molecules and their Interaction Relevant to Biology

The 6-membered cyclic form of sugars is usually called the “pyranose” form in reference to the cyclic ether pyran.

TLS Online TPP Program

#Id: 7852

#Unit 1. Molecules and their Interaction Relevant to Biology

The pyranose forms of the sugars are more stable than the furanose forms in solution.

TLS Online TPP Program

#Id: 7853

#Unit 1. Molecules and their Interaction Relevant to Biology

Thus, D glucose in aqueous solution exists as an equilibrium mixture of 5 compounds. The pyranose form predominates in solution.

aD glucofuranose (0.5%)

aD-glucopyranose (37%)

aldehydo- -glucose (0.003%)

bD-glucofuranose (0.5%)

bD-glucopyranose (62%)

TLS Online TPP Program

#Id: 7854

#Unit 1. Molecules and their Interaction Relevant to Biology

The optical activity of a stereoisomer is expressed quantitatively by its optical rotation.

The number of degrees by which plane-polarized light is rotated on passage through a given path length of a solution of the compound at a given concentration.

TLS Online TPP Program

#Id: 7855

#Unit 1. Molecules and their Interaction Relevant to Biology

Optical rotation