• The Korean Journal of Zoology
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• v.33 no.2
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• pp.158-165
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• 1990

Proteolytic activity of calpain was found to increase as myoblast fusion proceeds. At 60 hr after cell seeding, lis activity reached to a maximal level and then slighdy decreased thereafter. Similarly, the protein level of calpain reached to a maximal level just proir to the initiation of fusion and remained elevated upon prolonged culture as analyzed by immunoblol using anti-calpain antiserum. These results suggest that the synthesis of calpain is regulated during myogenesis and its proteolytic activity may be related with the process of myoblasts fusion.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1001-1004
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• 2006

The m-calpain activity hydrolyzing a fluorogenic substrate of N-Succinyl-Leu-Leu-Val-Tyr-7-amino-4-methylcourmarin (LLVY-AMC) was significantly stimulated by more than two-fold in the presence of 5$\mu$M $\alpha$synuclein at $15{^{\circ}C}$. The stimulation was also confirmed with azocasein. The stimulation of the peptide hydrolyzing activity required structural intactness of $\alpha$-synuclein since the C-terminally or N-terminally modified proteins such as $\beta$-synuclein, $\alpha$-syn1-97, and $\alpha$-syn61-140 did not increase the proteolytic activity. Instead, however, the N-terminally truncated $\alpha$-syn61-140 was shown to drastically suppress the calpain activity. Since the N-terminal truncation was known to be the primary cleaving event of calpain-mediated proteolysis of $\alpha$-synuclein and the $\alpha$-syn61-140 has been demonstrated to be resistant against the calpain digestion, it has been proposed that the intracellular calpain activity could be regulated in a reciprocal manner by $\alpha$-synuclein and its proteolyzed C-terminal fragment. Based on the results, a possible physiological function of $\alpha$-synuclein has been suggested as a calpain regulator which contains both stimulatory and inhibitory activities.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1653-1658
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• 2002

The objectives of this study were to examine calpain activity and meat tenderness by three different feeding patterns in Korean native cattle (KNC). Total forty-five animals were assigned each fifteen in long term restriction feeding (LTFR), long-term restriction feeding and hormone treatment (LTFR-tH), and short term non-restriction feeding (STFNR), respectively. Concentrate was restricted based on body weight in exp 1 and 2. However, it was fed ad libitum in exp. 3. Hormonal implantation was made with $M-PO^{TM}$ for bulls and with $F-TO^{TM}$ for heifers at 18, 20, 22 months of age in exp. 2. Animals were purchased (3-5 month old) from local cattle market and managed in two local farms and university research unit at three different years. Animals were slaughtered at 24 months for long-term trial and at 18 month for short term-trial. Loin and tender loin muscle was used for calpain activity and meat quality. Calpain proteolytic system was not changed by treatment. However, calpastatin activity was low in short-term trial. The calpain and calpastatin activity is reciprocal relationship, therefore, the high calpain activity may effect on quality grade. The shear force value was decreased as the processing of aging after postmortem. On the other hand, the cooking loss was significantly higher in short-term than in long-term trial, and then gradually decreased by the aging. Hormone implants to increase meat yield influenced to calpastatin activity more powerfully than calpain activity to meat tenderness. In meat color-a*, there was not significant difference in loin. Meat color-b* was decreased as postmortem aging time increased in tenderloin. Western blots were done to learn whether these proteins are degraded during postmortem storage and whether this degradation temporally parallels the decrease of shear force value. Vinculin was detected at 0 day and 1 day and degraded after 3 day. In conclusion, Calpain activity was affected slightly on meat tenderness. But meat tenderness was influenced by calpastatin, more effectively.

• Animal Bioscience
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• v.35 no.2
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• pp.272-280
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• 2022

Objective: The aim of this study was to evaluate the effect of ageing and feeding strategies on the calpain protease system and meat quality traits in Braford steers. Methods: Thirty Braford steers were employed; 15 animals were supplemented with corn silage during finishing and 15 were kept only on pasture. Meat quality traits and calpain system protein activity were evaluated in longissimus thoracis et lumborum (LTL) steaks aged for 2, 7, 14, and 21 days. Results: Aged meat showed higher pH and calcium content, while Warner Bratzler shear force (WBSF) decreased to day 21. No interaction between ageing and diet was seen for quality traits. Steers finished with corn silage showed higher values of water holding capacity, WBSF and free calcium, and lower values of pH and cooking loss. Calpain and calpastatin activities decreased with ageing. Finishing steers on pasture produced higher values of calpains and lower values of calpastatin activities. The higher values of calpain 1 activity were observed in muscles aged 2 days from pasture finished animals, and the lower activity of the inhibitor in the 21 days aged samples of the same group. Conclusion: These results suggest a diet by ageing interaction in calpains and calpastatin and this interaction impact in Warner Bratzler Shear Force in Braford LTL muscle.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1747-1753
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• 2002

The objectives of this study were to examine the effect of early short-term temperature conditioning on metabolic rate and calpain/calpastatin system and to compare variations in metabolic rate and calpain/calpastatin system between Hanwoo and Holstein beef. Longissimus thoracis et lumborum of the right carcass from 3 Hanwoo and 3 Holstein bulls were removed within 30 min of exsanguinations, cut into three pieces, and then temperature conditioned until 3 h postmortem (PM) at 2, 16, and $30^{\circ}C$, respectively. Rigor values (R-values; $R_248$, $R_250$, and $R_258$), pH, muscle temperature, glycogen content, $\mu$- and m-calpain activities, and calpastatin acitivity were measured at 1, 3, 9, and 24 h PM, respectively. Hanwoo beef had higher muscle temperature, faster metabolic rate at early PM stage in R-values, and lower $\mu$-calpain activity than Holstein beef (p<0.05). The $30^{\circ}C$ treatment maintained muscle temperature of $30^{\circ}C$ until 3 h PM and resulted in faster pH decline at 3 and 9 h PM (p<0.05) than other treatments. The $16^{\circ}C$ had higher (p<0.05) muscle temperature at 3 h PM than the $2^{\circ}C$, but no difference in all other traits was observed between the $2^{\circ}C$ and the $16^{\circ}C$. Early shortterm temperature treatment used in this study was not sufficient to effectively activate calpain/calpastatin system. Correlations among all traits except m-calpain and muscle temperature were generally high (r>0.60; p<0.001). Among R-values, $R_258$ had higher correlations with other metabolic traits than those of $R_248$ and $R_250$. These data suggest that early PM metabolic rate, $\mu$-calpain activity, and calpastatin activity may be closely related to each other. Variations in metabolic rate and $\mu$-calpain activity at early PM stage between Hanwoo and Holstein beef may imply variations in meat quality between both breeds.

• Animal cells and systems
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• v.5 no.4
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• pp.267-274
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• 2001

Calpains are a family of cysteine proteases existing primarily in two forms designated by the $Ca^{2+}$ concentration needed for activation in vitro, $\mu$-calpain (calpain-I) and m-calpain (calpain-II). The physiologica1 roles of calpains remain unclear. Many groups have proposed a role for calpains In apoptosis, but their patterns of activation are not well characterized. Calpains have been implicated in neutrophil apoptosis, glucocorticoid-induced thymocyte apoptosis, as well as many other apoptotic pathways. Calpain activation in apoptosis is usually linked upstream or downstream to caspase activation, or in a parallel pathway alongside caspase activation. Calpains have been suggested to be involved in DNA fragmentation (via endonuclease activation), but also as effector proteases that cleave cellular proteins involved in DNA repair, membrane associated proteins and other homeostatic regulatory proteins. Recently, our laboratory demonstrated $\mu$-calpain activation in NAD(P)H: quinone oxidoreducatse 1 (NQO1)-expressing cells after exposure to $\beta$-lapachone, a novel quinone and potential chemo- and radio-therapeutic agent. Increased cytosolic $Ca^{2+}$ in NQO1-expressing cells after $\beta$-lapachone exposures were shown to lead to $\mu$-calpain activation. In turn, $\mu$-calpain activation was important for substrate proteolysis and DNA fragmentation associated with apoptosis. Upon activation, $\mu$-calpain translocated to the nucleus where it could proteolytically cleave PARP and p53. We provided evidence that $\beta$-lapachone-induced, $\mu$-calpain stimulated, apoptosis did not involve any of the known caspases; known apoptotic caspases were not activated after $\beta$-lapachone treatment of NQO1-expressing cells, nor did caspase inhibitors have any effect on $\beta$-1apachone-induced cell death. Elucidation of processes by which $\beta$-1apachone-stimulated $\mu$-calpain activation and calpains ability to activate endonucleases and induce apoptosis independent of caspase activity will be needed to further develop/modulate $\beta$-lapachone for treatment of human cancers that over-express NQO1.

• Journal of Integrative Natural Science
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• v.7 no.1
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• pp.25-38
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• 2014

Amyloid-${\beta}$-peptide ($A{\beta}$) is important in the pathogenesis of Alzheimer's disease (AD). Calpain ($Ca^{2+}$-dependent protease) and caspase-8 (the initiating caspase for the extrinsic, receptor-mediated apoptosis pathway) have been implicated in $AD/A{\beta}$ toxicity. We found that $A{\beta}$ promoted degradation of calpastatin (the specific endogenous calpain inhibitor); calpastatin degradation was prevented by inhibitors of either calpain or caspase-8. The results implied a cross-talk between the two proteases and suggested that one protease was responsible for the activity of the other one. In neuron-like differentiated PC12 cells, calpain promotes active caspase-8 formation from procaspase-8 via the $A{\beta}$ and CD95 pathways, along with degradation of the procaspase-8 processing inhibitor caspase-8 (FLICE)-like inhibitory protein, short isoform (FLIPS). Inhibition of calpain (by pharmacological inhibitors and by overexpression of calpastatin) prevents the cleavage of procaspase-8 to mature, active caspase-8, and inhibits FLIPS degradation in the $A{\beta}$-treated and CD95-triggered cells. Increased cellular Ca2+ per se results in calpain activation but does not lead to caspase-8 activation or FLIPS degradation. The results suggest that procaspase-8 and FLIPS association with cell membrane receptor complexes is required for calpain-induced caspase-8 activation. The results presented here add to the understanding of the roles of calpain, caspase- 8, and CD95 pathway in $AD/A{\beta}$ toxicity. Calpain-promoted activation of caspase-8 may have implications for other types of CD95-induced cell damage, and for nonapoptotic functions of caspase-8. Inhibition of calpain may be useful for modulating certain caspase-8-dependent processes.

• Parasites, Hosts and Diseases
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• v.53 no.6
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• pp.665-673
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• 2015

After invasion of red blood cells, malaria matures within the cell by degrading hemoglobin avidly. For enormous protein breakdown in trophozoite stage, many efficient and ordered proteolysis networks have been postulated and exploited. In this study, a potential interaction of a 60-kDa Plasmodium falciparum (Pf)-heat shock protein (Hsp60) and Pf-calpain, a cysteine protease, was explored. Pf-infected RBC was isolated and the endogenous Pf-Hsp60 and Pf-calpain were determined by western blot analysis and similar antigenicity of GroEL and Pf-Hsp60 was determined with anti-Pf-Hsp60. Potential interaction of Pf-calpain and Pf-Hsp60 was determined by immunoprecipitation and immunofluorescence assay. Mizoribine, a well-known inhibitor of Hsp60, attenuated both Pf-calpain enzyme activity as well as P. falciparum growth. The presented data suggest that the Pf-Hsp60 may function on Pf-calpain in a part of networks during malaria growth.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.515-529
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• 2018

The present study was designed to investigate the effects of calpain system on the formation of volatile flavor compounds in Hanwoo beef. In the first experiment (exp.1), Longissimus lumborum (LL) muscle samples were injected with solutions containing 50 mM $CaCl_2$ or 50 mM $ZnCl_2$ and 154 mM NaCl respectively, and aged for 7 d at $4^{\circ}C$. In the second experiment (exp.2), the ground LL muscle was incubated with the aforementioned solutions containing cathepsin inhibitor. The injection with $CaCl_2$ solution greatly elevated the calpain activity and concomitantly, significantly decreased the Warner-Bratzler shear force (p<0.05). The pH, meat color and cooking loss did not differ (p>0.05) between the treatment groups. A total of 51 volatile compounds were identified using the solid phase microextraction with gas chromatography (SPME-GC). Results on volatile analyses from the both experiments showed that the injection with calcium ions led to significant increase (p<0.05) concentrations of pyrazines and sulfuric compounds. These results coincide with a higher rate of protein degradation due to the $CaCl_2$ injection as compared to the control group. Significantly (p<0.05) higher levels of lipid oxidation derived-aldehydes were found in the samples with $ZnCl_2$. The exp.1 showed that cathepsin inhibitors had no effect on the formation of volatile flavor components after 7 d of aging. These results imply that the proteolytic activity of the calpain system is associated with generation of volatile compounds of chiller-aged beef, while the role of cathepsins is likely very limited.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.310-315
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• 2005

The changes in pH, temperature, R-values and ${\mu}-calpain$ and its inhibitor activity of M. longissimus from Hanwoo steer were investigated at 1, 3, 9 and 24h postmortem. The pH and temperature of M. longissimus were significantly (p<0.05) decreased during 24h postmortem time, and were 6.50 and $31.99^{\circ}C$, respectively, at 3h postmortem. $R_{248}\;and\;R_{250}$ were increased, but $R_{258}$ was decreased after 9h postmortem time (p<0.05). Calpain I and calpastatin activity were decreased after 3h and 9h postmortem time, respectively (p<0.05). pH and temperature showed high positive correlations with $R_{258}$ (r=0.967 and r=0.970, respectively), calpain I (r =0.956 and r=0.954, respectively) and calpastatin (r=0.978 and r=0.986, respectively) but had high negative correlations with $R_{248}$ (r=-0.982 and r=-0.973, respectively) and $R_{248}$ (r=-0.983 and r=-0.976, respectively). from these results, the change of postmortem metabolism of M. longissimus from Hanwoo steer likely occurred after 9h postmortem time. However, the further study on the establishment of metabolism from Hanwoo between postmortem 3h and 9h are necessary to produce Hanwoo beef with high acceptance in meat quality.