title: Extremely acidic beta-1,4-glucanase, CelA4, from thermoacidophilic Alicyclobacillus sp. A4 with high protease resistance and potential as a pig feed additive.
abstract: An acidic endo-beta-1,4-glucanase, denoted CelA4 ( approximately 48 kDa), was purified from thermoacidophilic Alicyclobacillus sp. A4. Two internal peptides of CelA4 showed strong sequence identity to the Alicyclobacillus acidocaldarius cellulase precursor and contained the conserved domain and catalytic region of glycoside hydrolase family 51 beta-1,4-glucanases, and the N-terminal and three other internal peptides had no close glucanase or cellulase relatives, suggesting that the enzyme might be novel. CelA4 had broad substrate specificity, exhibited maximum activity at 65 degrees C and pH 2.6, was stable over pH 1.8-7.6, and showed strong resistance to acidic and neutral proteases, notably pepsin. In comparison to the commercial endo-beta-1,3-1,4-glucanase, CelA4 was more stable, released more reducing sugar from barley beta-glucan, and under simulated gastric conditions, decreased the viscosity of barley-soybean feed to a greater extent. These properties make CelA4 a good candidate as a new commercial glucanase to improve the nutrient bioavailability of pig feed.
authors.affiliation: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute.
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Bai
authors.forename: Jianshe
authors.initials: J
authors.lastname: Wang
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Huoqing
authors.initials: H
authors.lastname: Huang
authors.forename: Yukun
authors.initials: Y
authors.lastname: Feng
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D056450:Alicyclobacillus / Q000737:chemistry / Q000201:enzymology*; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002480:Cellulase / Q000737:chemistry* / Q000378:metabolism; D004795:Enzyme Stability; D005503:Food Additives / Q000737:chemistry*; D010447:Peptide Hydrolases / Q000737:chemistry; D013379:Substrate Specificity; D013552:Swine
chemical_list: D001426:Bacterial Proteins; D005503:Food Additives; C074775:CelA endoglucanase; D002480:Cellulase; D010447:Peptide Hydrolases