Catalytic properties and mode of action of endo-(1→3)-β- d-glucanase and β- d-glucosidase from the marine mollusk Littorina kurila

• Published in: Carbohydrate research 2008-09, Vol.343 (14), p.2393-2400
• Main Authors: Pesentseva, Maria S., Kusaykin, Mikhail I., Anastyuk, Stanislav D., Sova, Victoria V., Zvyagintseva, Tatyana N.
• Format: Article
• Language: English
• Subjects: (1→3)-β- d-Glucan; (1→3)-β- d-Glucanase; Animals; Endo-1,3-beta-Glucanase - chemistry; Endo-1,3-beta-Glucanase - isolation & purification; Endo-1,3-beta-Glucanase - metabolism; Glucans; Glucosidases - chemistry; Glucosidases - isolation & purification; Glucosidases - metabolism; Hydrogen-Ion Concentration; Hydrolysis; Liver - enzymology; Marine Biology; Marine mollusk; Mode of action; Molecular Weight; Nuclear Magnetic Resonance, Biomolecular; Polysaccharides - metabolism; Snails - enzymology; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Substrate Specificity; β-Glucosidase
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2008.06.025

A complex of the enzymes from the liver of the marine mollusk Littorina kurila that hydrolyzes laminaran was investigated. Two (1→3)-β- d-glucanases (G-I and G-II) were isolated. The molecular mass of G-I as estimated by gel-permeation chromatography and SDS–PAGE analysis was 32 and 40 kDa, respectively. The G-II molecular mass according to SDS–PAGE analysis was about 200 kDa. The pH optimum for both G-I and G-II was pH 5.4. The G-I had narrow substrate specificity and hydrolyzed only the (1→3)-β- d-glucosidic bonds in the mixed (1→3),(1→6)- and (1→3),(1→4)-β- d-glucans down to glucose and glucooligosaccharides. This enzyme acted with retention of the anomeric configuration and catalyzed a transglycosylation reaction. G-I was classified as the glucan endo-(1→3)-β- d-glucosidase (EC 3.2.1.39). G-II exhibited both exo-glucanase and β- d-glucoside activities. This enzyme released from the laminaran glucose as a single product, but retained the anomeric center configuration and possessed transglycosylation activity. The hydrolysis rate of glucooligosaccharides by G-I decreased with an increase of the substrate’s degree of polymerization. In addition to (1→3)-β- d-glucanase activity, the enzyme had the ability to hydrolyze p-nitrophenyl β- d-glucoside and β- d-glucobioses: laminaribiose, gentiobiose, and cellobiose, with the rate ratio of 50:12:1. G-II may correspond to β- d-glucoside glucohydrolase (EC 3.2.1.21).