The effect of sarcoplasmic protein phosphorylation on glycolysis in postmortem ovine muscle

Effects of slurry ice treatment on the physicochemical changes and proteome of large yellow croaker (Larimichthys crocea)

Large yellow croaker (Larimichthys crocea) is susceptible to oxidative denaturation during storage. This work is to investigate the quality alterations by analyzing its physicochemical changes and proteomics throughout preservation under refrigeration, frozen, and slurry ice (SI) conditions. Results revealed that the freshness of large yellow croaker, as evaluated by indicators such as total volatile basic nitrogen, total viable count, and thiobarbituric acid reactive substances, was well maintained while stored in the SI group. Meanwhile, the water distribution in the muscle tissue of group SI exhibited slower fluctuations, thereby preserving the integrity of fish muscle cells. Based on label-free proteomic analysis, a considerable downregulation was observed in the mitogen-activated protein kinase (MAPK) signaling pathway, indicating that SI decelerated this metabolic pathway and effectively delayed the deterioration of muscle. Therefore, the application of SI provides potential for maintaining the quality stability of large yellow croaker.

Correlation analysis of phosphorylation of myofibrillar protein and muscle quality of tilapia during storage in ice

In this study, the correlation between protein phosphorylation and deterioration in the quality of tilapia during storage in ice was examined by assessing changes in texture, water-holding capacity (WHC), and biochemical characteristics of myofibrillar protein throughout 7 days of storage. The hardness significantly decreased from 471.50 to 252.17 g, whereas cooking and drip losses significantly increased from 26.5% to 32.6% and 2.9% to 9.1%, respectively (P < 0.05). Myofibril fragmentation increased, while myofibrillar protein sulfhydryl content and Ca2+-ATPase activity decreased from 119.33 to 89.29 μmol/g prot and 0.85 to 0.46 μmolPi/mg prot/h, respectively (P < 0.05). Correlation analysis revealed that the myofibrillar protein phosphorylation level was positively correlated with hardness and Ca2+-ATPase activity but negatively correlated with WHC. Myofibrillar protein phosphorylation affects muscle contraction by influencing the dissociation of actomyosin, thereby regulating hardness and WHC. This study provides novel insights for the establishment of quality control strategies for tilapia storage based on protein phosphorylation.

An impact of l-histidine on the phosphorylation and stability of pyruvate kinase at low NaCl level

As one of the key rate limiting enzymes in glycolysis process, the characteristics of pyruvate kinase (PK) play an important role in regulating the muscle quality. Given the close relationship between kinase phosphorylation level and its stability, the present study investigated the impact of exogenous l-histidine (l-his) on PK phosphorylation and activity at 1% NaCl level in the early postmortem. An incubation system was also constructed and the results showed that the introduction of 0.06% l-his caused the dephosphorylation and increased the activity of PK at 1% NaCl. Compared with 1% NaCl treatment, three differential phosphorylation sites were produced when l-his was introduced. The PK secondary structure was shift from order to disorder, leading to a distinct degradation. This present study provided us with inspiration that meat quality could be improved by exogenous l-his at early postmortem under low NaCl conditions.

Effects of different protein phosphorylation levels on the tenderness of different ultimate pH beef

This study investigated the relationship between tenderness and protein phosphorylation levels of normal ultimate pH (pHu, 5.4-5.8, NpHu), intermediate pHu (5.8-6.2, IpHu) and high pHu (≥6.2, HpHu) Longissimus lumborum from beef. During 21 d of ageing, the HpHu group had the lowest Warner-Bratzler shear force (WBSF) values, while the IpHu group showed the highest and even after 21 days of ageing still had high levels. In the late stage of the 24 h post-mortem period the faster degradation rate of troponin T and earlier activation of caspase 9 in the HpHu group were the key reasons for the lower WBSF compared with the NpHu and IpHu groups. The activity of caspase 3 cannot explain the tenderness differences between IpHu and HpHu groups, since their activities did not show any difference. At 24 h post-mortem, 17 common differential phosphorylated peptides were detected among pHu groups, of which nine were associated with pHu and WBSF. The higher phosphorylation level of glycogen synthase may have caused the delay of meat tenderization in the IpHu group.

A Role of Multi-Omics Technologies in Sheep and Goat Meats: Progress and Way Ahead

Sheep and goat meats are increasingly popular worldwide due to their superior nutritional properties and distinctive flavor profiles. In recent decades, substantial progress in meat science has facilitated in-depth examinations of ovine and caprine muscle development during the antemortem phase, as well as post-mortem changes influencing meat attributes. To elucidate the intrinsic molecular mechanisms and identify potential biomarkers associated with meat quality, the methodologies employed have evolved from traditional physicochemical parameters (such as color, tenderness, water holding capacity, flavor, and pH) to some cutting-edge omics technologies, including transcriptomics, proteomics, and metabolomics approaches. This review provides a comprehensive analysis of multi-omics techniques and their applications in unraveling sheep and goat meat quality attributes. In addition, the challenges and future perspectives associated with implementing multi-omics technologies in this area of study are discussed. Multi-omics tools can contribute to deciphering the molecular mechanism responsible for the altered the meat quality of sheep and goats across transcriptomic, proteomic, and metabolomic dimensions. The application of multi-omics technologies holds great potential in exploring and identifying biomarkers for meat quality and quality control, thereby promoting the optimization of production processes in the sheep and goat meat industry.

Multi-Omics Approaches to Improve Meat Quality and Taste Characteristics

With rapid advances in meat science in recent decades, changes in meat quality during the pre-slaughter phase of muscle growth and the post-slaughter process from muscle to meat have been investigated. Commonly used techniques have evolved from early physicochemical indicators such as meat color, tenderness, water holding capacity, flavor, and pH to various omic tools such as genomics, transcriptomics, proteomics, and metabolomics to explore fundamental molecular mechanisms and screen biomarkers related to meat quality and taste characteristics. This review highlights the application of omics and integrated multi-omics in meat quality and taste characteristics studies. It also discusses challenges and future perspectives of multi-omics technology to improve meat quality and taste. Consequently, multi-omics techniques can elucidate the molecular mechanisms responsible for changes of meat quality at transcriptome, proteome, and metabolome levels. In addition, the application of multi-omics technology has great potential for exploring and identifying biomarkers for meat quality and quality control that can make it easier to optimize production processes in the meat industry.

Phosphorylation and acetylation responses of glycolytic enzymes in meat to different chilling rates

The aim of this study was to investigate the effects of chilling rate on phosphorylation and acetylation levels of the glycolytic enzymes in meat, including glycogen phosphorylase, phosphofructokinase, aldolase (ALDOA), triose-phosphate isomerase (TPI1), phosphoglycerate kinase, lactate dehydrogenase (LDH). The samples were assigned into three groups: Control, Chilling 1 and Chilling 2, corresponding to the chilling rates of 4.8 °C/h, 23.0 °C/h and 25.1 °C/h respectively. The contents of glycogen and ATP were significantly higher in samples from the chilling groups. The activity and phosphorylation level of the six enzymes were higher in samples at the chilling rate of 25.1 °C/h, while the acetylation level of ALDOA, TPI1 and LDH were inhibited. In brief, glycolysis was delayed and the activity of glycolytic enzymes were maintained at higher level by the changes of phosphorylation and acetylation levels at the chilling rates of 23.0 °C/h and 25.1 °C/h, which may partly explain why very fast chilling improves meat quality.

Phosphorylated Protein Levels in Animal-Sourced Food Muscles Based on Fe3+ and UV/Vis Spectrometry

Protein phosphorylation, a post-translational modification of proteins, is important in biological regulation. The quantity of phosphorylated proteins is a key requirement for the quality change of animal muscle foods. In the present study, a new approach to quantify phosphorylated proteins and/or peptides was developed based on ferric ions (Fe³⁺) and UV/vis spectrometry. This method is proved to be ultra-effective in discriminating phosphopeptides and non-phosphopeptides with the assistance of Fe³⁺. The protocol of extracting proteins with 0.1% trifluoroacetic acid (TFA) solution from animal muscle samples coupled with Fe³⁺ was verified by using an artificial mixture of peptides with different phosphorylation sites and was successfully used to characterize the phosphorylation quantity in the samples via UV/vis spectrometry. A peptide with one phosphorylated site was taken as a reference standard and successfully utilized for the absolute quantification of phosphorylated proteins in caprine muscles during frozen storage and in fish muscle food samples. This present study paves a new way for the evaluation of phosphorylated protein quantitative levels in bio-samples.

Integrated proteomic, phosphoproteomic, and N-glycoproteomic analyses of the longissimus thoracis of yaks

Yaks (Bos mutus) live in the Qinghai–Tibet plateau. The quality of yak meat is unique due to its genetic and physiological characteristics. Identification of the proteome of yak muscle could help to reveal its meat-quality properties. The common proteome, phosphoproteome, and N-glycoproteome of yak longissimus thoracis (YLT) were analyzed by liquid chromatography-tandem mass spectrometry-based shotgun analysis. A total of 1812 common proteins, 1303 phosphoproteins (3918 phosphorylation sites), and 204 N-glycoproteins (285 N-glycosylation sites) were identified in YLT. The common proteins in YLT were involved mainly in myofibril structure and energy metabolism; phosphoproteins were associated primarily with myofibril organization, regulation of energy metabolism, and signaling; N-glycoproteins were engaged mainly in extracellular-matrix organization, cellular immunity, and organismal homeostasis. We reported, for the first time, the “panorama” of the YLT proteome, specifically the N-glycoproteome of YLT. Our results provide essential information for understanding post mortem physiology (rigor mortis and aging) and the quality of yak meat.

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A total of 2650 proteins were identified in yak longissimus thoracis.

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Common proteins were involved mainly in myofibril structure and energy metabolism.

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Phosphoproteins were associated with myofibrils, energy metabolism, and signaling.

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N-glycoproteins were engaged mainly in ECM organization, immunity, and homeostasis.

Effects of protein posttranslational modifications on meat quality: A review

Meat quality plays an important role in the purchase decision of consumers, affecting producers and retailers. The formation mechanisms determining meat quality are intricate, as several endogenous and exogenous factors contribute during antemortem and postmortem periods. Abundant research has been performed on meat quality; however, unexpected variation in meat quality remains an issue in the meat industry. Protein posttranslational modifications (PTMs) regulate structures and functions of proteins in living tissues, and recent reports confirmed their importance in meat quality. The objective of this review was to provide a summary of the research on the effects of PTMs on meat quality. The effects of four common PTMs, namely, protein phosphorylation, acetylation, S-nitrosylation, and ubiquitination, on meat quality were discussed, with emphasis on the effects of protein phosphorylation on meat tenderness, color, and water holding capacity. The mechanisms and factors that may affect the function of protein phosphorylation are also discussed. The current research confirms that meat quality traits are regulated by multiple PTMs. Cross talk between different PTMs and interactions of PTMs with postmortem biochemical processes need to be explored to improve our understanding on factors affecting meat quality.

The combined effect of asparagus juice and balsamic vinegar on the tenderness, physicochemical and structural attributes of beefsteak

The adverse effects of chemical compounds have limited their usage despite their relative success in improving meat tenderness. Thus, natural tenderizers have attracted attention. The present study aimed to evaluate the tenderization effects of asparagus (Asparagus officinalis L.) juice and balsamic vinegar on beefsteak; marination at 4 °C for 48 h significantly increased the water-holding capacity, total protein solubility, myofibrillar fragmentation index and hydroxyproline content but significantly decreased the pH value, Warner-Bratzler shear force, and energy to the peak rates (P < 0.05). Scanning electron microscopy images and electrophoresis findings revealed extensive degradation of connective tissues and changes in protein band patterns, respectively. The tenderness of the beefsteak samples was optimum by applying 25% asparagus juice, and 25% asparagus juice + 10% balsamic vinegar. Therefore, marinade solutions containing asparagus juice and balsamic vinegar can be considered as natural tenderizing agents in formulation of seasonings and sauces to promote tenderness in tough beefsteak and possibly improve other quality-related properties.

Quantitative phosphoproteomic analysis provides insights into the aluminum-responsiveness of Tamba black soybean

Aluminum (Al3+) toxicity is one of the most important limitations to agricultural production worldwide. The overall response of plants to Al3+ stress has been documented, but the contribution of protein phosphorylation to Al3+ detoxicity and tolerance in plants is unclear. Using a combination of tandem mass tag (TMT) labeling, immobilized metal affinity chromatography (IMAC) enrichment and liquid chromatography-tandem mass spectrometry (LC-MS/MS), Al3+-induced phosphoproteomic changes in roots of Tamba black soybean (TBS) were investigated in this study. The Data collected in this study are available via ProteomeXchange with the identifier PXD019807. After the Al3+ treatment, 189 proteins harboring 278 phosphosites were significantly changed (fold change > 1.2 or < 0.83, p < 0.05), with 88 upregulated, 96 downregulated and 5 up-/downregulated. Enrichment and protein interaction analyses revealed that differentially phosphorylated proteins (DPPs) under the Al3+ treatment were mainly related to G-protein-mediated signaling, transcription and translation, transporters and carbohydrate metabolism. Particularly, DPPs associated with root growth inhibition or citric acid synthesis were identified. The results of this study provide novel insights into the molecular mechanisms of TBS post-translational modifications in response to Al3+ stress.

Acetylation and Phosphorylation of Proteins Affect Energy Metabolism and Pork Quality

Preslaughter handling has been shown to significantly affect meat quality, but the mechanisms are not fully understood. In this study, we investigated protein phosphorylation and acetylation in pig muscles at early postmortem time and their associations with meat quality attributes. Thirty pigs were randomly assigned to traditional (TH, n = 15) or mild handling (MH, n = 15). Compared with TH, MH reduced the incidence of pale, soft, and exudative (PSE) or dark, firm, and dry (DFD) pork. MH induced 65 and 20 peptides that match with 39 and 12 proteins to be more highly phosphorylated and acetylated, respectively. Creatine kinase, β-enolase, α-1,4-glucan phosphorylase, tropomyosin, and myosin heavy chain isoforms 1, 4, and 7 were found to be simultaneously phosphorylated and acetylated, which may involve glycolysis, tight junctions, and muscle contraction. The phosphorylation and acetylation levels of differential proteins showed significant correlations with meat quality traits. These findings indicate that preslaughter MH can improve meat quality by regulating protein phosphorylation and acetylation involving energy metabolism in muscle.

Effects of phosphorylation on the activity of glycogen phosphorylase in mutton during incubation at 4 °C in vitro

The aim of this study was to assess the effects of the phosphorylation levels of glycogen phosphorylase on its activity in mutton sarcoplasmic protein samples during incubation at 4 °C. Samples of sarcoplasmic proteins from mutton longissimus thoracis muscles were prepared and separated into three treatment groups to obtain glycogen phosphorylase with different phosphorylation levels, which were (1) treated with protein kinase A, (2) treated with alkaline phosphatase, and (3) left untreated (control). Glycogen phosphorylase phosphorylation levels and activity as well as the levels of related endogenous substances were assessed. The results showed that phosphorylation of glycogen phosphorylase in mutton promoted its activity during incubation at 4 °C. The activity of glycogen phosphorylase was also influenced by other factors (glycogen, glucose, glucose 6-phosphate, ATP, etc.) in vitro. The combined effects of phosphorylation and endogenous substances on glycogen phosphorylase activity varied at different incubation times.

Role of phosphorylation on characteristics of glycogen phosphorylase in lamb with different glycolytic rates post-mortem

The relationship between glycogen phosphorylase activity and phosphorylation levels in the longissimus thoracis muscle post-mortem was studied. Sixty lamb samples were collected at 0.5 h, 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h post-mortem and divided into three groups (n = 6) with different glycolytic rates (fast, intermediate, and slow) according to the pH at 6 h post-mortem. The phosphorylation level and activity and expression of glycogen phosphorylase were determined. The results showed that the phosphorylation level and activity of glycogen phosphorylase in the slow pH decline group was lower than that in the fast pH decline group during 24 h post-mortem (P < .05). There was a significant positive correlation between the glycogen phosphorylase activity and the phosphorylation level. In conclusion, these data demonstrated that the glycogen phosphorylase activity in lambs was affected by phosphorylation levels and postmortem duration.

Effects of temperature on protein phosphorylation in postmortem muscle

BACKGROUND

Phosphorylation is one of the most important post-translational modifications. Currently, many postmortem protein phosphorylation studies in muscle have been related to meat quality such as tenderness and color stability. However, the effects of various storage temperatures (25, 15, 4 and -1.5 °C) on the phosphorylation level of protein are poorly understood. Changes in the protein phosphorylation levels in postmortem ovine muscle at various storage temperatures were determined in this study.

RESULTS

The obtained data showed that pH decline rate was significantly inhibited at -1.5 °C from 12 h to 7 days postmortem (P < 0.05). The ATP consumption rate was higher at 25 °C than that at other three temperatures (P < 0.05). Analysis of the temperature, pH and ATP content revealed that the ATP content was related to the phosphorylation levels of individual protein bands. Phosphorylated myofibrillar and sarcoplasmic proteins, such as myosin binding protein C, troponin T3, myosin light chain 1, glucose-6-phosphate isomerase and pyruvate kinase, were mainly involved in glycolysis and muscle contraction.

CONCLUSION

The global and specific protein phosphorylation levels can be influenced by the postmortem storage temperature of muscle. Phosphorylation of proteins was correlated with glycolysis and muscle contraction. Certain phosphorylated proteins, such as heat shock proteins, require further study to clarify their effects on meat traits. © 2019 Society of Chemical Industry.