User:Kassaray/Inulinase

Article Draft

Lead

Inulinase has 2 EC numbers of 3.2.1.7 and 3.2.1.8 , for endo- and -exo inulinases, respectively. This classifies it as a hydrolase, specifically a glycosylase of glycosidic nature capable of hydrolyzing O- and S- glycosyl. Due to its chemical reactions, the food industry uses this enzyme to create high fructose syrup. It can be extracted from many tuber vegetables, such as Jerusalem artichoke, dahlia, and chicory.

Article body

Enzyme's reaction pathway

The enzymatic reaction occurs between the inulinase and the inulin, with the assistance of water via hydrolysis. It's typically done within one step . The reaction centers around the breakage of a bond. The products result in fructose syrup and fructo-oligosaccharide. When these products undergo fermentation, additional products may be formed: lactic acid, bioethanol, citric acid, etc. The mechanisms involved may be considered highly efficient when compared to other enzymes.

Where It Can Be Found

Jerusalem artichokes, native to North America

There are several places and ways for inulinase to be found and produced. A common way is via plants, usually tubular root vegetables (Jerusalem artichoke, dahlia, chicory).

Another way is via bacteria (fungal endophyte, Kluyveromyces marxianus, Cryptococcus aureus). Marine bacteria, yeasts, and fungi are used commonly as well.

Aspergillus sp, a bacteria which can produce inulin

How It Functions Within Cell

As a catalytic enzyme, either endo- or -exo inulinase destroys the bonds of one fructose attached to the inulin chain. Various affinities depending on the environment will affect how the inulinase interacts with the inulin. It functions efficiently between 40-80 degrees Celsius, although depending on the source of the enzyme, it can go as low as 30 degrees Celsius and still work well .

Known crystal structures

Crystal structure of hydrolase endo-inulinase from Bifidobacterium adolescentis expressed in Escherichia coli

Crystal structure of hydrolase exo-inulinase from Aspergillus awamori

The crystal structures are shown here on either side of the page. The two structures of endo-inulinase and exo-inulinase are mainly made of beta-sheets, with the exception of the endo-inulinase, which has one alpha helix. Being made of beta sheets allows the structures to be more stable during chemical reactions.

Known active sites & Structure tied to function

Both of the inulinases have different active sites, with exo-inulinase having a funnel shape whereas endo-inulinase has a pocket shape. . They're complicated due to the amino acids needing to be a balance of catalytic and conserved to achieve a stable enzymatic active site. According to the most recent reference, three amino acids (serine, aspartic acid, and glutamic acid) bind via a hydrogen bond to the fructose molecule that attaches to the exo-inulinase. Whereas with three other amino acids (glutamic acid, tryptophan, and asparagine) those bind via a hydrogen bond to the ketose molecule that attaches to the endo-inulinase.