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Determination of exponential rate constants for calpain-mediated degradation of myofibrillar complexed proteins Albisser, Tracie
Abstract
The purpose of this study was to test the hypothesis that an orderly sequence or time course of calpain action on purified myofibrillar/cytoskeletal complexes from cardiac and fast muscle tissue exists. To test the response of individual substrate proteins to degradation (i.e. susceptibility), exogenous calpain (1.5U/ml) was incubated with 40 ug of highly purified rat myofibrillar complexes from cardiac and gastrocnemius muscles (0 to 60 min), in vitro. Apparent molecular weights (SDS-PAGE) were used to compare and identify individual myofibril proteins. Myofibrillar yields for cardiac (n=9) and fast skeletal (n=9) muscles were 62.93 ± 6.58 and 98.42 ± 9.36 mg/g (p<0.05). Following 30 minutes of calpain treatment, the amount of cardiac desmin, C-protein, a-actinin and troponin-T remaining in complex were 0%, 19%, 23% and 68%, compared to controls (p<0.05). For fast skeletal muscle, the remaining desmin, C-protein, a-actinin and tropomyosin after 30 minutes of calpain digestion was 0%, 38%, 51% and 17%, respectively, compared to control (p<0.05). The estimated exponential rate constants (k) for degradation/loss for each protein (in both tissues) had the following order: desmin>C-protein>a -actinin (p<0.05). The results of this study support the hypothesis that there are selective degradation rates and an ordered sequence of degradation for myofibrillar complexed proteins. Factors contributing to the heterogeneity of k values for myofibril proteins, and therefore their susceptibility to calpain degradation, may be their spatial arrangement (peripheral -> central) within the myofibril and/or their primary amino acid residue composition.
Item Metadata
Title |
Determination of exponential rate constants for calpain-mediated degradation of myofibrillar complexed proteins
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1996
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Description |
The purpose of this study was to test the hypothesis that an orderly sequence or
time course of calpain action on purified myofibrillar/cytoskeletal complexes from cardiac
and fast muscle tissue exists. To test the response of individual substrate proteins to
degradation (i.e. susceptibility), exogenous calpain (1.5U/ml) was incubated with 40 ug of
highly purified rat myofibrillar complexes from cardiac and gastrocnemius muscles (0 to
60 min), in vitro. Apparent molecular weights (SDS-PAGE) were used to compare and
identify individual myofibril proteins. Myofibrillar yields for cardiac (n=9) and fast skeletal
(n=9) muscles were 62.93 ± 6.58 and 98.42 ± 9.36 mg/g (p<0.05). Following 30 minutes
of calpain treatment, the amount of cardiac desmin, C-protein, a-actinin and troponin-T
remaining in complex were 0%, 19%, 23% and 68%, compared to controls (p<0.05). For
fast skeletal muscle, the remaining desmin, C-protein, a-actinin and tropomyosin after 30
minutes of calpain digestion was 0%, 38%, 51% and 17%, respectively, compared to
control (p<0.05). The estimated exponential rate constants (k) for degradation/loss for
each protein (in both tissues) had the following order: desmin>C-protein>a -actinin
(p<0.05). The results of this study support the hypothesis that there are selective
degradation rates and an ordered sequence of degradation for myofibrillar complexed
proteins. Factors contributing to the heterogeneity of k values for myofibril proteins, and
therefore their susceptibility to calpain degradation, may be their spatial arrangement
(peripheral -> central) within the myofibril and/or their primary amino acid residue
composition.
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Extent |
6687849 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-03-07
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0077157
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1997-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.