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A proteolytic enzyme regulated by the concentration of calcium ions.

[Probably cal(cium) + p(rote)a(se) + -in.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


any of various enzymes in mammals and other organisms that are involved in the proteolysis of endogenous proteins and are regulated by the concentration of calcium ions
[C20: from cal(modulin) + (pa)pain]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
The autolysis of meat occurs with the active participation of lysosome enzymes-cathepsins and calpains (Hope-Jones, 2010).
(i) Inactivation of endogenous proteases, especially calpains (the most important being [micro]-calpain): these enzymes need a reducing substrate to carry out their action, given the presence of functional groups -SH (thiols) which are subject to oxidation; however, the role of this mechanism is debated, as some authors highlighted the marginal role of calpains in meat tenderization [35, 72].
Greer, "Ubiquitous calpains promote caspase-12 and JNK activation during endoplasmic reticulum stress-induced apoptosis," The Journal of Biological Chemistry, vol.
Murphy, "Calpains, skeletal muscle function and exercise," Clinical and Experimental Pharmacology and Physiology, vol.
Enzymes such as caspases, calpains, thrombin, and cathepsins cleave tau.[39] Experiments in vitro indicate that caspases 1, 3, 6, 7, and 8 can cleave tau at different sites, resulting in the generation of truncated tau species which are primed for subsequent phosphorylation.[40],[41] Calpain activity is regulated by a calcium-dependent heat-stable inhibitor, calpastatin.
The calpain superfamily is complex, and more than 25 calpains or calpain-like molecules have been discovered.
As excessive myoplasmic [Ca.sup.2+] concentration activates calpains that cleave a variety of substrates, including myofibrillar proteins [24, 29, 30], calpain-mediated degradation could contribute to the ultrastructural alterations observed in [RYR1.sup.Y522S/WT] muscle fibers.
Calpains are a family of calcium-activated cysteine proteases that catalyze the limited proteolysis of a number of cellular proteins in eukaryotes [18, 19].
The calpastatin (CAST) which has been found in all the tissues that contain calpains, is a specific inhibitor of calpain enzymes (Lonergan et al., 2010).
This axonal disintegration process is mediated by the activation of calcium-dependent proteases, such as calpains, that target cytoskeleton proteins, especially neurofilaments, for degradation (10).
Therefore, a greater proportion of oxidative fibers reflect in lower activity of calpains, due to a larger amount of calpastatin, resulting in lower muscle degradation and originating a less tender meat (Koohmaraie, 1996).