Isopullulanase

Related Reading

Amylases belong to the class of hydrolytic enzymes, a collective name for a class of enzymes that catalyze the glycosidic bonds in starch, glycogen and dextrin. Amylases are widely distributed in nature and are contained in almost all plants, animals and microorganisms. It is one of the most studied, earliest produced, most widely used and most produced enzymes, and its production accounts for more than 50 % of the total production of enzymes. According to its origin, it can be divided into bacterial amylase, mycobacterial amylase and maltose amylase.

Isopullulanase

Isopullulanase hydrolyzes only the -1,6 glycosidic chain at the branching point of glycogen or branched starch, cutting off the entire side branch to form straight-chain starch of varying length. The characteristics of the action of isopullulanase on the substrate can be confirmed by the properties of the product after its action on glutinous rice starch. When isopullulanase acts on glutinous rice starch, with the unbranching action, the iodine color reaction changes from red to blue, the reducing power increases, precipitation occurs in butanol, the starch solution becomes easily aged, and the characteristics of straight-chain starch appear. A striking phenomenon when isopullulanase is used in combination with other amylases is that it leads to complete saccharification of starch.

Principle

In fact, isopullulanase was discovered as early as 1940 from yeast extracts, but it took a not too short period of time to understand the enzymatic properties of isopullulanase. With the advancement of starch chemistry, the amylase was better understood. We realized that the color change of the above iodine reaction was related to the properties of branched chain starch and straight chain starch, and the so-called starch synthase was actually an enzyme that cut the '6 glycosidic bond. We renamed this enzyme as isopullulanase.

Principle

Isopullulanase is widely found in nature. In plants. Isopullulanase is found in rice, broad beans, potatoes, malt and sweet corn. In the liver and muscle of higher animals, there are also enzymes that break down the II-1,6 glycosidic bond similar to isopullulanase. There are many strains of microorganisms that can produce isopullulanase. In addition to yeast, many bacteria and some actinomycetes have been found to produce isopullulanase. Moreover, it is known that different sources of isopullulanases have different specificity of action on the substrate.

Applications

The main application of isopullulanase is in the decomposition of various branched polysaccharides and thrombomycin. By the 1970s, the application of isopullulanase has been extended to a number of starch deep processing fields such as starch syrup, beer and alcohol production, and gradually moved from the laboratory stage to the industrial scale. In starch processing, isopullulanase can accelerate the saccharification process and improve the saccharification rate when it is synergistic with glycosylase, and can greatly improve the maltose yield when it is combined with β-amylase, so it is a branched chain amylase in great demand. At present, it has been successfully applied in the production of high glucose syrup, high maltose syrup, oligosaccharide and beer, and also in the field of medicine.