title: Catalytic properties and mode of action of endo-(1-->3)-beta-D-glucanase and beta-D-glucosidase from the marine mollusk Littorina kurila.
abstract: A complex of the enzymes from the liver of the marine mollusk Littorina kurila that hydrolyzes laminaran was investigated. Two (1-->3)-beta-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 40kDa, respectively. The G-II molecular mass according to SDS-PAGE analysis was about 200kDa. 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)-beta-d-glucosidic bonds in the mixed (1-->3),(1-->6)- and (1-->3),(1-->4)-beta-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)-beta-d-glucosidase (EC 3.2.1.39). G-II exhibited both exo-glucanase and beta-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)-beta-d-glucanase activity, the enzyme had the ability to hydrolyze p-nitrophenyl beta-d-glucoside and beta-d-glucobioses: laminaribiose, gentiobiose, and cellobiose, with the rate ratio of 50:12:1. G-II may correspond to beta-d-glucoside glucohydrolase (EC 3.2.1.21).
authors.affiliation: Pacific Institute of Bioorganic Chemistry, Far East Branch of Russian Academy of Sciences, 690022 Vladivostok, 159 Prospect 100 let Vladivostoku, Russia.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Pesentseva
authors.forename: Mikhail I
authors.initials: MI
authors.lastname: Kusaykin
authors.forename: Stanislav D
authors.initials: SD
authors.lastname: Anastyuk
authors.forename: Victoria V
authors.initials: VV
authors.lastname: Sova
authors.forename: Tatyana N
authors.initials: TN
authors.lastname: Zvyagintseva
mesh_terms: D000818:Animals; D044644:Endo-1,3(4)-beta-Glucanase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D005936:Glucans; D005959:Glucosidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008099:Liver / Q000201:enzymology; D008386:Marine Biology; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D011134:Polysaccharides / Q000378:metabolism; D012908:Snails / Q000201:enzymology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity
chemical_list: D005936:Glucans; D011134:Polysaccharides; C008247:laminaran; D005959:Glucosidases; D044644:Endo-1,3(4)-beta-Glucanase