IMIS | Lifewatch regional portal

You are here


[ report an error in this record ]basket (0): add | show Print this page

Intrinsic halotolerance of the psychrophilic alpha-amylase from Pseudoalteromonas haloplanktis
Srimathi, S.; Jayaraman, G.; Feller, G.; Danielsson, B.; Narayanan, P.R. (2007). Intrinsic halotolerance of the psychrophilic alpha-amylase from Pseudoalteromonas haloplanktis. Extremophiles 11(3): 505-515.
In: Extremophiles. Springer: Tokyo. ISSN 1431-0651; e-ISSN 1433-4909, more
Peer reviewed article  

Available in  Authors 

    Pseudoalteromonas haloplanktis (ZoBell & Upham, 1944) Gauthier, Gauthier & Christen, 1995 [WoRMS]
Author keywords
    acidic protein; Pseudoalteromonas haloplanktis alpha-amylase;halophilic; halotolerance; psychrophilic; stability

Authors  Top 
  • Srimathi, S.
  • Jayaraman, G.
  • Feller, G., more
  • Danielsson, B.
  • Narayanan, P.R.

    The halotolerance of a cold adapted α-amylase from the psychrophilic bacterium Pseudoalteromonas haloplanktis (AHA) was investigated. AHA exhibited hydrolytic activity over a broad range of NaCl concentrations (0.01–4.5 M). AHA showed 28% increased activity in 0.5–2.0 M NaCl compared to that in 0.01 M NaCl. In contrast, the corresponding mesophilic (Bacillus amyloliquefaciens) and thermostable (B. licheniformis) α-amylases showed a 39 and 46% decrease in activity respectively. Even at 4.5 M NaCl, 80% of the initial activity was detected for AHA, whereas the mesophilic and thermostable enzymes were inactive. Besides an unaltered fluorescence emission and secondary structure, a 10°C positive shift in the temperature optimum, a stabilization factor of >5 for thermal inactivation and a ΔTm of 8.3°C for the secondary structure melting were estimated in 2.7 M NaCl. The higher activation energy, half-life time and Tm indicated reduced conformational dynamics and increased rigidity in the presence of higher NaCl concentrations. A comparison with the sequences of other halophilic α-amylases revealed that AHA also contains higher proportion of small hydrophobic residues and acidic residues resulting in a higher negative surface potential. Thus, with some compromise in cold activity, psychrophilic adaptation has also manifested halotolerance to AHA that is comparable to the halophilic enzymes.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors