Purification and characterization of a thermostable, haloalkaliphilic extracellular serine protease from the extreme halophilic archaeon Halogeometricum borinquense strain TSS101

MALASHETTY VIDYASAGAR ； S. PRAKASH ； CAROL LITCHFIELD ； K. SREERAMULU

《Archaea》 2006卷 (2006/12) Pp. 51-57

https://doi.org/10.1155/2006/430763

摘要

Anovel haloalkaliphilic, thermostable serine proteasewas purified from the extreme halophilic archaeon, Halogeometricum borinquense strain TSS101. The protease was isolated from a stationary phase culture, purified 116-fold with 18% yield and characterized biochemically. The molecular mass of the purified enzyme was estimated to be 86 kDa. The enzyme showed the highest activity at 60 °C and pH 10.0 in 20% NaCl. The enzyme had high activity over the pH range from 6.0 to 10.0. Enzymatic activity was strongly inhibited by 1 mM phenyl methylsulfonyl fluoride, but activity was increased 59% by 0.1% cetyltrimethylammonium bromide. The enzyme exhibited relatively high thermal stability, retaining 80% of its activity after 1 h at 90 °C. Thermostability increased in the presence of Ca^(2+). The stability of the enzyme was maintained in 10% sucrose and in the absence of NaCl.

關鍵字

calcium chloride ； cetyltrimethylammonium bromide ； halophilic serine protease ； metal ions ； osmolytes ； protease inhibitors