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Calcium-supported Calpain Degradation Rates for Cardiac Myofibrils in Diabetes. Sulfhydryl and Hydrophobic Interactions

Overview
Publisher Springer
Specialty Biochemistry
Date 1994 Jun 15
PMID 7816056
Citations 4
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Abstract

Objective: The purpose was to investigate the calcium required for calpain-mediated degradation of selected cardiac myofibril proteins modified by diabetes, sulfhydryl (SH) and hydrophobic reagents.

Methods: After 20 weeks of streptozotocin-induced (55 mg.kg-1) diabetes, calcium sensitive calpain (1.5 U.ml-1) degradation rates of purified cardiac myofibrillar proteins (1 mg.ml-1) were measured, in vitro, and compared to degradation rates for N-ethylmaleimide (NEM) and 2-p-toluidinylnapthalene-6-sulfonate (TNS) treated samples.

Results: Diabetes (blood glucose of 550 +/- 32 mg.dl-1) reduced the yield of purified myofibrillar protein with minimal change in fibril protein composition. Total SH group reactivities (nmol.mg-1.30min) were 220 +/- 21, 163 +/- 17 and 156 +/- 24 for control, diabetic and NEM-treated (0.5 mM) myofibrils (p < or = 0.05). Calpain degradation rates were faster for all diabetic and SH modified myofibrillar proteins (p < or = 0.05), with a 45 and 35% reduction in the pCa50 for a 37 kDa protein of diabetic and NEM-treated fibril complexes. For control myofibrils, both 100 and 200 uM TNS, reduced calpain degradation rates to a similar extent for all substrate proteins. In contrast, diabetic and NEM-treated samples showed a further reduction in calpain degradation rates with increasing TNS from 100 to 200 uM.

Conclusion: Our results support the hypothesis that in diabetes the calcium requirements for calpain degradation rates are reduced and dependent upon sulfhydryl group status and Ca(2+)-induced hydrophobic interactions, implicating a 37 kDa myofbillar-complexed protein.

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References
1.
Thompson E . Structural manifestations of diabetic cardiomyopathy in the rat and its reversal by insulin treatment. Am J Anat. 1988; 182(3):270-82. DOI: 10.1002/aja.1001820308. View

2.
Laemmli U . Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970; 227(5259):680-5. DOI: 10.1038/227680a0. View

3.
Anderson W, Gopalakrishna R . Functional and regulatory importance of calcium-mediated hydrophobic regions of calmodulin, protein kinase C, and other calcium-binding proteins. Curr Top Cell Regul. 1985; 27:455-69. DOI: 10.1016/b978-0-12-152827-0.50046-3. View

4.
Gilchrist J, Wang K, Katz S, Belcastro A . Calcium-activated neutral protease effects upon skeletal muscle sarcoplasmic reticulum protein structure and calcium release. J Biol Chem. 1992; 267(29):20857-65. View

5.
Murachi T . Intracellular regulatory system involving calpain and calpastatin. Biochem Int. 1989; 18(2):263-94. View