Experimental evidence for a 9‐binding subsite of Bacillus licheniformis thermostable α‐amylase. Issue 4 (17th January 2014)

• Record Type: Journal Article
• Authors: Tran, Phuong Lan; Lee, Jin-Sil; Park, Kwan-Hwa
• Is Part Of: FEBS letters. Volume 588:Issue 4(2014)
• Page Start: 620
• Page End: 624
• Publication Date: 2014-01-17
• Subjects: Bacillus licheniformis thermostable α-amylase -- Kinetic parameter -- Subsite affinity -- Linear maltooligosaccharides -- High-performance anion exchange chromatography; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1016/j.febslet.2013.12.032
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : The action pattern of Bacillus licheniformis thermostable α‐amylase (BLA) was analyzed using a series of 14 C‐labeled and non‐labeled maltooligosaccharides from maltose (G2) to maltododecaose (G12). Maltononaose (G9) was the preferred substrate, and yielded the smallest K m = 0.36 mM, the highest k cat = 12.86 s −1, and a k cat / K m value of 35.72 s −1 mM −1, producing maltotriose (G3) and maltohexaose (G6) as the major product pair. Maltooctaose (G8) was hydrolyzed into two pairs of products: G3 and maltopentaose (G5), and G2 and G6 with cleavage frequencies of 0.45 and 0.30, respectively. Therefore, we propose a model with nine subsites: six in the terminal non‐reducing end‐binding site and three at the reducing end‐binding site in the binding region of BLA. Abstract : B. licheniformis α‐amylase produces mainly maltohexaose from maltooctaose and maltononaose. Maltononaose gave the smallest K m value and the highest k cat . The enzyme has nine subsites: six in the non‐reducing and three at the reducing end‐binding site.