enzymes.co.uk > questions about enzymes > 45. invertase
45. From Claire in Manchester AnthnyWrgg@aol.com
How does invertase work in the hydrolysis of sucrose?
Sucrose (what we know as household sugar) is actually two sugars joined together. The proper term for this is a disaccharide. Sucrose consists of a glucose and fructose molecule joined together. The systematic scientific name for sucrose is glucose-alpha-(1-2)-fructose. Other disaccharides include lactose (found in milk = galactose-beta(1-4)-glucose) and maltose (found in malt, due to the breakdown of starch by beta-amylase = glucose-alpha-(1-4)-glucose).
The systematic name for invertase is beta-fructofuranosidase and the designated number is EC 220.127.116.11 In the human body the enzyme that does the same function as invertase is called sucrase (see question 16). The term "invertase" usually refers to enzyme from either fungal/bacterial or plant sources.
Invertase splits the bond between the two sugars by hydrolysis (see answer 40). Invertase belongs to a class of enzymes known as glycosidases. Some of these enzymes work by simply splitting the bond while others work by twisting the bond at the same time. These enzymes that twist the bond at the same time as splitting it result in one of the released sugars being in a slightly different configuration than when it started so that it is inverted from alpha to beta. I think invertase was the first enzyme where this was studied and so that it is why it was called invertase.
also on enzymes.co.uk
question 16: info about sucrase
links outside enzymes.co.uk
enzyme nomenclature: www.expasy.ch/enzyme
"Biochemistry" by Lubert Stryer 3rd edition 1988
Page created April 12, 2002 NSheehan
Last modified April12, 2002