O. V. Gudzenko¹*, L. D. Varbanets¹, V. O. Chernyshenko², E. M. Stognii²

¹D.K. Zabolotny Institute of Microbiology and Virology,
National Academy of Sciences of Ukraine, Kyiv;
²Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: alena.gudzenko81@gmail.com

Received: 18 September 2025; Revised: 13 October 2025;
Accepted: 28 November 2025; Available on-line:          2025

Previously, we isolated a number of Bacillus sp. strains from the dry grass of the coastal zone of the Kinburn Spit, which may be promising for further research as producers of proteases with fibrinolytic and fibrinogenolytic activity. The aim of the work was to isolate, purify and study the properties of fibrin(ogen)ase from the Bacillus sp. L9 strain. The enzyme preparation was isolated from the supernatant of the Bacillus sp. L9 culture liquid. The yield of the purified enzyme was 1.8%, the specific fibrinogenolytic and fibrinolytic activities were 483 and 383 U/mg protein, respectively, the molecular weight of the enzyme was about 40 kDa, the optimum pH was 8.0, and the thermooptimum was 40°C. Bacillus sp. L9 fibrin(ogen)ase is a serine protease, in the active center of which is the carboxyl group of the C-terminal (aspartic or glutamic) amino acid. At some distance from the active site are localized sulfhydryl groups that do not participate in catalysis, but play an important role in maintaining the catalytically active conformation of the protein molecule. The enzyme from Bacillus sp. L9 hydrolyzed fibrin molecules much more slowly than fibrinogen, and showed the greatest specificity in the hydrolysis of bonds formed by the Aα-chain of fibrinogen. According to the specifici­ty of action on fibrinogen, the enzyme was identified as α-fibrinogen(ogen)ase.

Keywords: Bacillus sp. L9; purification, fibrin(ogen)olytic enzyme, molecular weight, pH-, specificity, thermal optima