title: A bioconjugate of Pseudomonas cepacia lipase with alginate with enhanced catalytic efficiency.
abstract: A bioconjugate of Pseudomonas cepacia lipase with alginate was prepared by simple adsorption. Atomic force microscope (AFM) images showed that this bioconjugate resulted from adsorption rather than entrapment of the enzyme as enzyme molecules were visible on the gel surface. The soluble bioconjugate exhibited increased enzyme activity in terms of high effectiveness factor (effectiveness factor was 3 for the immobilized preparation) and greater Vmax/Km value (Vmax/Km increased 25 times upon immobilization). This constitutes one of the less frequently observed instances of lipase activation by lid opening as a result of binding to a predominantly hydrophilic molecule. The bioconjugate was also more stable at 55 degrees C as compared to the free enzyme and could be reused for oil hydrolysis up to 4 cycles without any loss in activity. Fluorescence emission spectroscopy showed that the immobilized enzyme had undergone definite conformational changes.
authors.affiliation: Chemistry Department, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016, India.
authors.forename: Kalyani
authors.initials: K
authors.lastname: Mondal
authors.forename: Payal
authors.initials: P
authors.lastname: Mehta
authors.forename: Bodh Raj
authors.initials: BR
authors.lastname: Mehta
authors.forename: Deepak
authors.initials: D
authors.lastname: Varandani
authors.forename: Munishwar Nath
authors.initials: MN
authors.lastname: Gupta
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D016956:Burkholderia cepacia / Q000201:enzymology*; D002384:Catalysis; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008049:Lipase / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D000464:Alginates; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D008049:Lipase