Abstract
Meat quality development is highly dependent on postmortem (PM) metabolism and rigor mortis development in PM muscle. PM glycometabolism and rigor mortis fundamentally determine most of the important qualities of raw meat, such as ultimate pH, tenderness, color and water-holding capacity. Protein phosphorylation is known to play essential roles on regulating metabolism, contraction and other important activities in muscle systems. However, protein phosphorylation has rarely been systematically explored in PM muscle in relation to meat quality. In this PhD project, both gel-based and mass spectrometry (MS)-based quantitative phosphoproteomic strategies were employed to analyze PM muscle with the aim to intensively characterize the protein phosphorylation involved in meat quality development.
Firstly, gel-based phosphoproteomic studies were performed to analyze the protein phosphorylation in both sarcoplasmic proteins and myofibrillar proteins from PM porcine muscle. Generally, the porcine muscle with fast pH decline rate had the highest phosphorylation level at 1 h PM, but lowest at 24 h PM, whereas the group with slow pH decline rate showed the reverse case. The protein phosphorylation level of sarcoplasmic proteins was significantly related to the synergy effects of pH and time, whereas that of myofibrillar proteins was mainly changed with PM time. In total, 72 unique proteins were identified in PM porcine muscle. In addition, electrical stimulation was also confirmed to affect protein phosphorylation level of sarcoplasmic proteins in beef. The majority of the identified phosphoproteins were glycometabolism related enzymes in the sarcoplasmic fraction and contraction related proteins in the myofibrillar fraction.
Subsequently, the quantitative LC-MS/MS-based phosphoproteomic strategy was used to identify and quantify the phosphorylation events in PM porcine muscle development. In total 305 unique proteins were identified in the PM porcine muscle proteome, including 160 phosphoproteins with 784 phosphorylation sites, among them, 184 phosphorylation sites on 93 proteins had their phosphorylation levels significantly changed within 24 h PM. Results revealed that proteins involved in glycometabolism and muscle contraction related roteins were the two largest clusters of phosphoproteins in PM muscle, and their hosphorylation patterns were significantly changed within 24 h PM. The slaughter stress may contribute to the higher phosphorylation level of heat shock proteins (HSPs) in earlier PM, such as the putative Serine 84 on HSP27.
These results indicated the involvement of protein phosphorylation in regulating meat quality development. PM muscle proteins underwent significant changes at phosphorylation level even though they were stable at total protein level. Protein phosphorylation may have important roles in meat quality development through the regulation of proteins involved in glycometabolism and muscle contraction, thereby affecting glycolysis and rigor mortis development in PM muscle.
Firstly, gel-based phosphoproteomic studies were performed to analyze the protein phosphorylation in both sarcoplasmic proteins and myofibrillar proteins from PM porcine muscle. Generally, the porcine muscle with fast pH decline rate had the highest phosphorylation level at 1 h PM, but lowest at 24 h PM, whereas the group with slow pH decline rate showed the reverse case. The protein phosphorylation level of sarcoplasmic proteins was significantly related to the synergy effects of pH and time, whereas that of myofibrillar proteins was mainly changed with PM time. In total, 72 unique proteins were identified in PM porcine muscle. In addition, electrical stimulation was also confirmed to affect protein phosphorylation level of sarcoplasmic proteins in beef. The majority of the identified phosphoproteins were glycometabolism related enzymes in the sarcoplasmic fraction and contraction related proteins in the myofibrillar fraction.
Subsequently, the quantitative LC-MS/MS-based phosphoproteomic strategy was used to identify and quantify the phosphorylation events in PM porcine muscle development. In total 305 unique proteins were identified in the PM porcine muscle proteome, including 160 phosphoproteins with 784 phosphorylation sites, among them, 184 phosphorylation sites on 93 proteins had their phosphorylation levels significantly changed within 24 h PM. Results revealed that proteins involved in glycometabolism and muscle contraction related roteins were the two largest clusters of phosphoproteins in PM muscle, and their hosphorylation patterns were significantly changed within 24 h PM. The slaughter stress may contribute to the higher phosphorylation level of heat shock proteins (HSPs) in earlier PM, such as the putative Serine 84 on HSP27.
These results indicated the involvement of protein phosphorylation in regulating meat quality development. PM muscle proteins underwent significant changes at phosphorylation level even though they were stable at total protein level. Protein phosphorylation may have important roles in meat quality development through the regulation of proteins involved in glycometabolism and muscle contraction, thereby affecting glycolysis and rigor mortis development in PM muscle.
| Original language | English |
|---|
| Publisher | Department of Food Science, University of Copenhagen |
|---|---|
| Number of pages | 143 |
| Publication status | Published - 2013 |