Related Experiment Videos
Kinetic characterization of alkaline mesentericopeptidase. Comparison with serine proteinases from different origins
P Dolaschka1, N Genov, A Ermer
1Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia.
Abstract:
Comparative studies of the hydrolysis of succinyl-Ala2-Phe-methylcoumarylamide with mesentericopeptidase, a mesophilic extracellular serine proteinase from Bacillus mesentericus, and proteinases produced by organisms representing different levels of evolutionary development, were performed. Drastic differences in the proteolytic coefficient kcat/Km were found. As regards their catalytic efficiency, the proteinases studied can be placed in the following order: mesentericopeptidase < subtilisin Novo << subtilisin DY < proteinase K < subtilisin Carlsberg < thermitase < alpha-chymotrypsin. The size of the substrate-binding site of mesentericopeptidase for synthetic peptides was studied by using chloromethyl ketones with the general formula benzyloxycarbonyl-Alan-Phe-CH2Cl (n = 1, 2, 3). The presence of at least five binding subsites (S1 ... S5) on the S-side of the hydrolysed bond was suggested. Studies of the primary specificity of mesentericopeptidase with a series of dipeptide chloromethyl ketones having the general formula benzyloxycarbonyl-Ala-Aa-CH2Cl (Aa = Ala, Val, Leu, Phe) revealed the following order of reactivity toward these inhibitors: Aa = Leu >> Ala > Phe > Val. Kinetically, mesentericopeptidase is similar to subtilisin BPN'/Novo.
Insights
Mesentericopeptidase, a bacterial serine proteinase, exhibits unique substrate specificity and catalytic efficiency compared to other proteases. Its binding site suggests at least five subsites for synthetic peptide hydrolysis.
Area of Science:
- Enzymology
- Biochemistry
- Molecular Biology
Background:
- Comparative analysis of enzyme kinetics and substrate specificity is crucial for understanding proteinase function.
- Mesentericopeptidase, a serine proteinase from Bacillus mesentericus, has not been extensively characterized in relation to other proteases.
Purpose of the Study:
- To compare the catalytic efficiency and substrate-binding site of mesentericopeptidase with various other proteinases.
- To elucidate the primary specificity of mesentericopeptidase using synthetic peptide substrates.
Main Methods:
- Hydrolysis of succinyl-Ala2-Phe-methylcoumarylamide by mesentericopeptidase and other proteinases.
- Enzyme kinetics were analyzed using the proteolytic coefficient (kcat/Km).
- Substrate-binding site size was investigated using chloromethyl ketone derivatives.
Main Results:
- Mesentericopeptidase demonstrated distinct catalytic efficiency (kcat/Km) compared to other studied proteinases, ranking lower than subtilisins and alpha-chymotrypsin.
- The enzyme's substrate-binding site accommodates at least five subsites (S1-S5).
- Primary specificity studies revealed a preference for leucine (Leu) in the P1 position of peptide substrates.
Conclusions:
- Mesentericopeptidase exhibits unique kinetic properties and substrate specificity, differing significantly from other serine proteinases.
- The enzyme's catalytic efficiency and binding site characteristics provide insights into its functional role.
- Mesentericopeptidase shares kinetic similarities with subtilisin BPN'/Novo, suggesting conserved catalytic mechanisms.