Catalytic properties of the cloned amylase from Bacillus licheniformis

• Published in: The Journal of biological chemistry Vol. 267; no. 31; pp. 22108 - 22114
• Main Authors: Kim, I.C. (Seoul National University, Suwon), Cha, J.H, Kim, J.R, Jang, S.Y, Seo, B.C, Cheong, T.K, Lee, D.S, Choi, Y.D, Park, K.H
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 05.11.1992
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ALFA AMILASA; ALPHA AMYLASE; Amino Acid Sequence; Amylases - genetics; Amylases - metabolism; Analytical, structural and metabolic biochemistry; Bacillus - enzymology; Bacillus - genetics; BACILLUS LICHENIFORMIS; Base Sequence; Biological and medical sciences; Carbohydrate Sequence; Catalysis; Chromatography, High Pressure Liquid; CLONACION; CLONAGE; Cloning, Molecular; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Genes, Bacterial; GENIE GENETIQUE; Glucans - metabolism; Hydrolases; Hydrolysis; INGENIERIA GENETICA; Molecular Sequence Data; NUCLEOTIDE; NUCLEOTIDOS; Sequence Alignment; Substrate Specificity; Bacillales; Enzymatic activity; Amylase; Enzyme; Bacillus licheniformis; Substrate specificity; HPLC chromatography; Bacteria; Primary structure; Bacillaceae; Molecular cloning; Mechanism of action
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)41642-0

A gene encoding a new amylolytic enzyme of Bacillus licheniformis (BLMA) has been cloned, and we characterized the enzyme expressed in Escherichia coli. The genomic DNA of B. licheniformis was double-digested with EcoRI and BamHI and ligated the pBR322. The transformed E. coli was selected by its amylolytic activity, which carries the recombinant plasmid pIJ322 containing a 3.5-kilobase fragment of B. licheniformis DNA. The purified enzyme encoded by pIJ322 was capable of hydrolyzing pullulan and cyclodextrin as well as starch. It was active over a pH range of 6-8 and its optimum temperature was 50 degrees C. The molecular weight of the enzyme was 64,000, and the isoelectric point was 5.4. It degraded soluble starch by cleaving maltose units preferentially but did not attack alpha-1,6-linkage. The enzyme also hydrolyzed pullulan to panose units exclusively. In the presence of glucose, however, it transferred the panosyl moiety to glucose with the formation of alpha-1,6-linkage. The specificity of transferring activity is evident from the result of the maltosyl-transferring reaction which produces isopanose from maltotriose and glucose. The molecular structure of the enzyme deduced from the nucleotide sequence of the clone maintains limited similarity in the conserved regions to the other amylolytic enzymes