Purification and characterization of a novel beta-agarase, AgaA34, from Agarivorans albus YKW-34.

Appl Microbiol Biotechnol

College of Food Science & Engineering, Ocean University of China, Qingdao, 266003, China.

Published: February 2008

An extracellular beta-agarase (AgaA34) was purified from a newly isolated marine bacterium, Agarivorans albus YKW-34 from the gut of a turban shell. AgaA34 was purified to homogeneity by ion exchange and gel filtration chromatographies with a recovery of 30% and a fold of ten. AgaA34 was composed of a single polypeptide chain with the molecular mass of 50 kDa. N-terminal amino acid sequencing revealed a sequence of ASLVTSFEEA, which exhibited a high similarity (90%) with those of agarases from glycoside hydrolase family 50. The pH and temperature optima of AgaA34 were pH 8.0 and 40 degrees C, respectively. It was stable over pH 6.0-11.0 and at temperature up to 50 degrees C. Hydrolysis of agarose by AgaA34 produced neoagarobiose (75 mol%) and neoagarotetraose (25 mol%), whose structures were identified by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy and (13)C NMR. AgaA34 cleaved both neoagarohexaose and neoagarotetraose into neoagarobiose. The k (cat)/K (m) values for hydrolysis agarose and neoagarotetraose were 4.04 x 10(3) and 8.1 x 10(2) s(-1) M(-1), respectively. AgaA34 was resistant to denaturing reagents (sodium dodecyl sulfate and urea). Metal ions were not required for its activity, while reducing reagents (beta-Me and dithiothreitol, DTT) increased its activity by 30%.

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00253-007-1303-3DOI Listing

Publication Analysis

Top Keywords

agaa34
8
beta-agarase agaa34
8
agarivorans albus
8
albus ykw-34
8
agaa34 purified
8
hydrolysis agarose
8
purification characterization
4
characterization novel
4
novel beta-agarase
4
agaa34 agarivorans
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!