Changes in Structural Properties of Porcine Myofibrillar Protein Induced by Frozen Storage

2012 ◽  
Vol 554-556 ◽  
pp. 1395-1399
Author(s):  
Xiu Fang Xia ◽  
Bao Hua Kong ◽  
Lian Zhou Jiang ◽  
Pei Jun Li ◽  
Qian Chen
Keyword(s):  
Atpase Activity ◽  
Myosin Heavy Chain ◽  
Structural Properties ◽  
Heavy Chain ◽  
Storage Temperature ◽  
Frozen Storage ◽  
Surface Hydrophobicity ◽  
Myofibrillar Protein ◽  
Longissimus Dorsi ◽  
Structure Property

Changes in structure property of myofibrillar protein from porcine longissimus dorsi were monitored during 12 months of storage at –5, –18, –26, –35 and –70 °C. With the extended frozen time at the same temperature, Ca2+-ATPase activity, K+-ATPase activity, total sulfhydryl content reactive sulfhydryl content decreased (P < 0.05), surface hydrophobicity (S0-NAS) increased (P < 0.05). Meanwhile, stucture of myofibrillar protein was more susceptible to high frozen storage temperature than low frozen storage temperature. There was markedly loss in band intensity of myosin heavy chain, actin, paramyosin, troponin, and propomyosin from frozen meat within frozen storage.

scholarly journals Effects of Frozen Storage Temperature and Duration on Changes in Physicochemical Properties of Beef Myofibrillar Protein

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shuyi Qian ◽  
Xia Li ◽  
Hang Wang ◽  
Waris Mehmood ◽  
Chunhui Zhang ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Storage Temperature ◽  
Protein Denaturation ◽  
Frozen Storage ◽  
Storage Period ◽  
Freezing Temperature ◽  
Surface Hydrophobicity ◽  
Myofibrillar Protein ◽  
Storage Duration ◽  
Quality Properties

This study aimed to address the effects of frozen storage temperature and duration on the changes in physicochemical properties of beef myofibrillar protein. The beef was stored at −1, −6, −9, −12, and −18°C for 28, 84, 126, 168, and 168 days, respectively. The myofibrillar protein of beef samples denatured gradually with the extention of storage period. Regarding the samples stored at temperature range of −12∼−1°C, higher storage temperature resulted in more severe denaturation (the myofibrillar protein exhibited lower sulfhydryl content, Ca2+-ATPase activity, ionic bonds, hydrogen bonds, and higher surface hydrophobicity). Particularly, difference in −12 and −18°C did not yield significant effects upon the protein properties throughout 168-day storage P > 0.05 . These results indicated that lowering freezing temperature may not minimize myofibrillar protein denaturation in a limited storage duration, which was also confirmed by the quality properties of beef.

Myosin heavy chain turnover in cultured neonatal rat heart cells: effects of [Ca2+]i and contractile activity

1996 ◽  
Vol 271 (5) ◽  
pp. C1447-C1456 ◽  
Author(s):  
K. L. Byron ◽  
J. L. Puglisi ◽  
J. R. Holda ◽  
D. Eble ◽  
A. M. Samarel
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Protein Turnover ◽  
Ventricular Myocytes ◽  
Contractile Activity ◽  
Myofibrillar Protein ◽  
Neonatal Rat ◽  
Heart Cells ◽  
Cell Shortening ◽  
Rat Heart Cells

Blockade of L-type Ca2+ channels in spontaneously contracting cultured neonatal rat ventricular myocytes causes contractile arrest, myofibrillar disassembly, and accelerated myofibrillar protein turnover. To determine whether myofibrillar protein turnover. To determine whether myofibrillar atrophy results indirectly from loss of mechanical signals or directly from alterations in intracellular Ca2+ concentration ([Ca2+]i), contractile activity was inhibited with verapamil (10 microM) or 2,3-butanedione monoxime (BDM), and their effects on cell shortening, [Ca2+]i, and myosin heavy chain (MHC) turnover were assessed. Control cells demonstrated spontaneous [Ca2+]i transients (peak amplitude 232 +/- 15 nM, 1-2 Hz) and vigorous contractile activity. Verapamil inhibited shortening by eliminating spontaneous [Ca2+]i transients. Low concentrations of BDM (5.0-7.5 mM) had no effect on basal or peak [Ca2+]i transient amplitude but reduced cell shortening, whereas 10 mM BDM reduced both [Ca2+]i transient amplitude and shortening. Both agents inhibited MHC synthesis, but only verapamil accelerated MHC degradation. Thus MHC half-life does not change in parallel with contractile activity but rather more closely follows changes in [Ca2+]i. [Ca2+]i transients appear critical in maintaining myofibrillar assembly and preventing accelerated MHC proteolysis.

Effects of triiodo-thyronine on angiotensin-induced cardiomyocyte hypertrophy: reversal of increased β-myosin heavy chain gene expression

2006 ◽  
Vol 84 (8-9) ◽  
pp. 935-941 ◽  
Author(s):  
Baohua Wang ◽  
Jingping Ouyang ◽  
Zhengyuan Xia
Keyword(s):  
Gene Expression ◽  
Angiotensin Ii ◽  
Thyroid Hormone ◽  
Cardiac Hypertrophy ◽  
Atpase Activity ◽  
Mrna Expression ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Ang Ii ◽  
Hypertrophic Growth

Thyroid hormone-induced cardiac hypertrophy is similar to that observed in physiological hypertrophy, which is associated with high cardiac contractility and increased α-myosin heavy chain (α-MHC, the high ATPase activity isoform) expression. In contrast, angiotensin II (Ang II) induces an increase in myocardial mass with a compromised contractility accompanied by a shift from α-MHC to the fetal isoform β-MHC (the low ATPase activity isoform), which is considered as a pathological hypertrophy and inevitably leads to the development of heart failure. The present study is designed to assess the effect of thyroid hormone on angiotensin II-induced hypertrophic growth of cardiomyocytes in vitro. Cardiomyocytes were prepared from hearts of neonatal Wistar rats. The effects of Ang II and 3,3′,5-triiodo-thyronine (T3) on incorporations of [3H]-thymine and [3H]-leucine, MHC isoform mRNA expression, PKC activity, and PKC isoform protein expression were studied. Ang II enhanced [3H]-leucine incorporation, β-MHC mRNA expression, PKC activity, and PKCε expression and inhibited α-MHC mRNA expression in cardiomyocytes. T3 treatment prevented Ang II-induced increases in PKC activity, PKCε, and β-MHC mRNA overexpression and favored α-MHC mRNA expression. Thyroid hormone appears to be able to reprogram gene expression in Ang II-induced cardiac hypertrophy, and a PKC signal pathway may be involved in such remodeling process.

Sliding velocity of isolated rabbit cardiac myosin correlates with isozyme distribution

1992 ◽  
Vol 263 (2) ◽  
pp. H464-H472 ◽  
Author(s):  
H. Yamashita ◽  
S. Sugiura ◽  
T. Serizawa ◽  
T. Sugimoto ◽  
M. Iizuka ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Motility Assay ◽  
Cardiac Myosin ◽  
Sliding Velocity ◽  
In Vitro Motility Assay ◽  
In Vitro Motility ◽  
Actin Cables

To investigate the relationship between the mechanical and biochemical properties of cardiac myosin, the sliding velocity of isolated cardiac myosin obtained from both euthyroid and hyperthyroid rabbits on actin cables was measured with an in vitro motility assay system. Ten rabbits (T) were treated with L-thyroxine to induce hyperthyroidism, and eight nontreated animals (N) were used as controls. Myosin was purified from the left ventricles of anesthetized animals. Myosin isozyme content was analyzed by the pyrophosphate gel electrophoresis method, and myosin adenosinetriphosphatase (ATPase) activity was determined on the same sample. Long well-organized actin cables of green algae, Nitellopsis, were used in the in vitro motility assay. Small latex beads were coated with purified cardiac myosin and introduced onto the Nitellopsis actin cables. Active unidirectional movement of the beads on the actin cables was observed under a photomicroscope, and the velocity was measured. The velocity was dependent on ATP concentrations, and the optimal pH for bead movement was approximately 7.0-7.5. The mean velocity was higher in T than in N (0.66 +/- 0.12 vs. 0.32 +/- 0.09 micron/s, P less than 0.01). Both Ca(2+)-activated ATPase activity and the percentage of alpha-myosin heavy chain were also higher in T than in N (0.691 +/- 0.072 vs. 0.335 +/- 0.072 microM Pi.mg-1.min-1, P less than 0.01, and 79 +/- 12 vs. 26 +/- 7%, P less than 0.01, respectively). The velocity of myosin closely correlated with both Ca(+2)-activated myosin ATPase activity (r = 0.87, P less than 0.01) and the percentage of alpha-myosin heavy chain (r = 0.87, P less than 0.01).

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