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Updated: Aug 13, 2026

The Importance of Correct Protein Concentration for Kinetics and Affinity Determination in Structure-function Analysis
Published on: March 17, 2010
Actinomycins as proteinase inhibitors
C Betzel1, R Rachev, P Dolashka
1European Molecular Biology Laboratory, Hamburg, Germany.
Abstract:
A novel actinomycin (Act SG3) from a strain of Streptomyces galbus var. C-72, as well as actinomycin D (Act D) were found to act as competitive inhibitors of serine proteinases from microorganisms. The inhibitory properties of Act SG3 and Act D are compared with these of other peptide antibiotics, namely bacitracin A (Bac A) and gramicidin S (Gr S). The last compound has only a weak inhibitory effect. The following order of affinity for the four peptide antibiotics towards subtilisin DY and proteinase K was observed: Bac A > Act D > Act SG3 = Gr S. The affinity towards thermitase changes as follows: Act SG3 = Act D > Bac A > Gr S.
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