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Subtilisin inhibitors in legume seeds
D S Seidl1, P Lorenzo, B E Pinelli
1Depto. Biologia Celular, Facultad de Ciencias, Universidad Central de Venezuela.
Biological Chemistry Hoppe-Seyler
|May 1, 1988
Summary
Subtilisin inhibitors (SI) from various beans show specific activity against microbial serine proteinases. Their varied interactions and reactive site cleavage suggest legume seed SIs may form a new proteinase inhibitor family.
Area of Science:
- Biochemistry
- Plant Science
- Enzymology
Background:
- Subtilisin inhibitors (SI) are proteins that regulate serine protease activity.
- Legume seeds are known sources of various bioactive compounds, including proteinase inhibitors.
Purpose of the Study:
- To compare subtilisin inhibitors purified from jack beans, broad beans, chick peas, and black beans.
- To investigate the specificity and reaction mechanisms of these legume-derived SIs with microbial serine proteinases.
Main Methods:
- Electrophoretic purification of SI from different legume seeds.
- Assessing SI specificity against microbial serine proteinases like subtilisin Carlsberg and Proteinase K.
- Analyzing the reactive site cleavage patterns of SI under varying pH conditions.
Main Results:
- SI from jack beans, broad beans, chick peas, and black beans exhibit specificity for microbial serine proteinases.
- Black bean SI showed the highest interaction with subtilisin Carlsberg, followed by broad bean, chick pea, and jack bean.
- Proteinase K reacted more strongly with SI than subtilisin.
- Legume SIs follow a standard inhibition mechanism involving reversible reactive site cleavage, with variations in pH dependency.
Conclusions:
- Legume seed-derived SIs share similarities in specificity, molecular mass, and heat stability.
- The observed characteristics suggest that SIs from various legume seeds could represent a novel family of proteinase inhibitors.