An extracellular - Pepstatin insensitive acid protease produced by Thermoplasma volcanium

Kocabiyik S., Ozel H.

BIORESOURCE TECHNOLOGY, vol.98, pp.112-117, 2007 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 98
  • Publication Date: 2007
  • Doi Number: 10.1016/j.biortech.2005.11.016
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.112-117
  • Keywords: Thermoplasma volcanium, acid protease, pepstatin-insensitive acid protease, thermostable, NUCLEOTIDE-SEQUENCE, CARBOXYL PROTEINASE, GENE, CLONING, PURIFICATION, BACTERIUM
  • Middle East Technical University Affiliated: Yes


In this study, some parameters for the production and caseinolytic activity of an extracellular thermostable acid protease from a thermoacidophilic archaeon Thermoplasma volcanium were determined. The highest level of growth and enzyme production were detected at pH 3.0 over an incubation period of 192 h at 60 degrees C. The pH optimum for the acid protease activity was 3.0 and the enzyme was fairly stable over a broad pH range (pH 3.0-8.0). The temperature for maximum activity of the enzyme was 55 degrees C and activity remained stable between 50 degrees C and 70 degrees C. These features could be of relevance for various biotechnological applications of this enzyme. Serine-(PMSF), cysteine-(DTT), metallo-(EDTA) and aspartate-(pepstatin) protease inhibitors did not inhibit the caseinolytic activity of the enzyme. Therefore, Tp. volcanium acid protease could be a member of the pepstatin-insensitive carboxyl proteinases. (c) 2005 Elsevier Ltd. All rights reserved.