Related Experiment Video
Updated: Aug 10, 2026
07:42
Dissection of Hippocampal Dentate Gyrus from Adult Mouse
Published on: November 17, 2009
Comparison of calpains from rabbit, monkey, human and rat
S Kawashima1, H Akanuma, K Asaoka
1Department of Molecular Biology, Tokyo Metropolitan Institute of Medical Science, Japan.
Biological Chemistry
|April 2, 1998
Summary
Calpain isozymes, mu-calpain and m-calpain, show variations in large subunit molecular mass and antigenic sites across species. These differences impact their Ca2+-sensitivity and antibody cross-reactivity, highlighting species-specific calpain characteristics.
Area of Science:
- Biochemistry
- Molecular Biology
- Proteolysis
Background:
- Calpains are calcium-dependent cysteine proteases involved in various cellular processes.
- Two major isozymes, mu-calpain and m-calpain, are widely distributed in mammalian tissues.
- Understanding species-specific variations in calpain structure and function is crucial for comparative biology and disease research.
Purpose of the Study:
- To compare the molecular masses, Ca2+-sensitivity, and immunoreactivity of mu-calpain and m-calpain from different animal species.
- To investigate the structural similarities and differences between calpain isozymes across rabbits, monkeys, humans, and rats.
Main Methods:
- Purification of mu-calpain and m-calpain isozymes from rabbit, monkey, human, and rat tissues to homogeneity.
- Direct comparison of apparent molecular masses of large and small subunits using SDS-PAGE.
- Assessment of Ca2+-sensitivity and Ca2+-dependency.
- Immunological characterization using monoclonal antibodies against rabbit m- and mu-calpains.
- Peptide mapping using V8 protease digestion.
Main Results:
- Small subunits of calpains were consistently 28 kDa across all species.
- Large subunit molecular masses varied: Rabbit mu (79 kDa), m (75 kDa); Monkey mu (79 kDa), m (74 kDa); Human mu (78 kDa), m (73 kDa); Rat mu (75 kDa), m (74 kDa).
- Monkey mu-calpain exhibited lower Ca2+-sensitivity than rabbit mu-calpain; rabbit and monkey m-calpains had similar Ca2+-dependency.
- Immunoreactivity varied for m-calpains, indicating shared and distinct antigenic sites. Rat mu-calpain showed minimal cross-reactivity, except with monoclonal 1D10A7.
- Peptide maps were similar between homologous isozymes from rabbit and monkey, but antibody cross-reactivity was weak, especially for mu-calpain.
Conclusions:
- Calpain isozymes exhibit significant species-specific variations in the large subunit's molecular mass and antigenic properties.
- These structural differences correlate with variations in Ca2+-sensitivity and antibody recognition.
- The monoclonal antibody 1D10A7 demonstrates broad reactivity across mu- and m-calpains from different species, suggesting conserved epitopes.
