| Резюме: |
The aim of the present investigation was to characterize collagenolytic enzymes produced by mesophilic and thermophilic actinomycetes strains in soil samples collected from different regions in Bulgarian and other countries. The cultivation conditions (pH, temperature, cultivation time, inoculum size and substrate concentration) for obtaining of high specific collagenase activity were optimized for two active strains - Streptomyces cremeus 3B and Thermoactinomyces sacchari 21E. The mesophilic streptomycete strain S. cremeus 3B constitutively secreted collagenolytic enzymes during the exponential growth phase. The enzymes, produced by S. cremeus 3B were purified in six steps, leading to two collagenases (I and II) with specific activity of 3350 and 3600 U/mg, respectively. Analysis of the purified enzymes by the method of zymography revealed that both, I and II were with relative molecular mass 116 and 97 kDa, respectively. Both enzymes belong to the "true" collagenases and resemble the clostridial enzymes. A thermostable collagenase, produced extracellular by thermophilic T. sacchari 21E was purified to homogeneity by five steps with a 101-fold increase in specific activity and 58 yield. The collagenase has a relative molecular mass of 50 kDa. The collagenase from T. sacchari 21E showed high activity toward type I collagen, acid-soluble collagen, gelatin and PZ-PLGPR. It suggests that this enzyme belongs to "true" collagenases.
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