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Characterization of cathepsins in cartilage
The Biochemical Journal
|November 1, 1967
Summary
Rabbit ear cartilage contains a cathepsin B-like enzyme that degrades matrix components. This enzyme, similar to an endogenous one, functions optimally at pH 4.7 and is sensitive to specific inhibitors.
Area of Science:
- Biochemistry
- Enzymology
- Cartilage Biology
Background:
- Cartilage degradation involves complex enzymatic processes.
- Understanding the enzymes responsible for matrix breakdown is crucial for cartilage health.
Purpose of the Study:
- To identify and characterize cathepsin B-like enzymes in rabbit ear cartilage.
- To compare the properties of cathepsin B-like enzymes with endogenous cartilage-degrading enzymes.
Main Methods:
- Incubation of thin cartilage sections with synthetic substrates (benzoyl-l-arginine amide and benzoyl-dl-arginine 2-naphthylamide).
- Enzyme activity assays at various pH levels.
- Assessment of enzyme inhibition by specific chemical agents and heat inactivation.
Main Results:
- A cathepsin B-like enzyme was detected in rabbit ear cartilage using synthetic substrates.
- Both cathepsin B-like and endogenous enzymes exhibit optimal activity at pH 4.7.
- Enzymes are enhanced by cysteine and inhibited by arginine analogues, iodoacetamide, chloroquine, and mercuric chloride, but not by EDTA or certain phosphate compounds.
- Enzymes are stable at acidic pH and unstable at neutral/alkaline pH.
Conclusions:
- Rabbit ear cartilage possesses a cathepsin B-like enzyme.
- This enzyme shares characteristics with an endogenous enzyme involved in cartilage matrix degradation.
- Cathepsin B-like enzymes may play a role in the autolytic degradation of cartilage matrix at acidic pH.