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1	Effects of protein modification on textural properties and water holding capacity of heat induced turkey breast meat gels Li, Xuesong 18 January 2008 The main objectives of this research were to examine effects of protein modification (protein cleavage and crosslinking) on turkey meat gelation and to evaluate textural properties and water holding capacity of meat gels prepared from normal and PSE (pale, soft, exudative) turkey breast meat.<p>First, the effect of protein degradation on turkey breast meat gelation was studied. To create different extent of proteolysis in the meat, á-chymotrypsin (EC 3.4.21.1) was added to normal and PSE meat batters at 0, 2.5, 5 and 10 ppm levels. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cooked meat gels showed progressive protein hydrolysis with increasing enzyme level. Texture profile analysis and torsional analysis of the cooked meat gels showed an incremental deterioration in texture with increasing enzyme level. This inferior texture caused by proteolysis was similar to that observed in the gels made from PSE turkey meat alone. Pearson correlation coefficients indicated gel textural properties and expressible moisture were highly correlated to the degree of proteolysis, especially to that of myosin heavy chain (p < 0.001).<p>The second study focused on modifying protein size to improve meat gelation, especially PSE meat gelation. Transglutaminase (TGase, EC 2.3.2.13) was chosen due to its ability to catalyze crosslinking of proteins. Pea protein isolate, an alternative to soy protein, was also evaluated as a meat protein extender. Textural profile and torsional gelometry analyses of the cooked meat gels showed TGase alone significantly (p < 0.05) increased gel texture, especially for those made from PSE meat. However, cook yield of the meat gels was compromised possibly due to steric effects. Addition of pea protein isolate alone improved cook yield and gel texture, especially for the gels made from PSE meat. The combination of TGase and pea protein produced the strongest meat gels, while maintaining a similar cook yield to the control. SDS-PAGE showed the disappearance of several protein bands contributed from the meat or pea protein with TGase addition, indicating that these likely were crosslinked and too large to enter the gel. Dynamic rheological analysis revealed TGase altered the viscoelastic properties of the meat or meat-pea protein mixtures and produced more elastic gels on cooling.<p>This research indicated proteolysis had a dramatic impact on textural properties of turkey breast meat gels. Crosslinking of proteins catalyzed by TGase significantly improved gel texture, especially for the gels made from PSE meat. However, TGase-assisted crosslinking of proteins resulted in greater cooking losses unless an extender/adjunct such as pea protein was added. PSE meat gel protein crosslinking protein degradation water holding capacity textural property
2	Effects of protein modification on textural properties and water holding capacity of heat induced turkey breast meat gels Li, Xuesong 18 January 2008 (has links) The main objectives of this research were to examine effects of protein modification (protein cleavage and crosslinking) on turkey meat gelation and to evaluate textural properties and water holding capacity of meat gels prepared from normal and PSE (pale, soft, exudative) turkey breast meat.<p>First, the effect of protein degradation on turkey breast meat gelation was studied. To create different extent of proteolysis in the meat, á-chymotrypsin (EC 3.4.21.1) was added to normal and PSE meat batters at 0, 2.5, 5 and 10 ppm levels. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cooked meat gels showed progressive protein hydrolysis with increasing enzyme level. Texture profile analysis and torsional analysis of the cooked meat gels showed an incremental deterioration in texture with increasing enzyme level. This inferior texture caused by proteolysis was similar to that observed in the gels made from PSE turkey meat alone. Pearson correlation coefficients indicated gel textural properties and expressible moisture were highly correlated to the degree of proteolysis, especially to that of myosin heavy chain (p < 0.001).<p>The second study focused on modifying protein size to improve meat gelation, especially PSE meat gelation. Transglutaminase (TGase, EC 2.3.2.13) was chosen due to its ability to catalyze crosslinking of proteins. Pea protein isolate, an alternative to soy protein, was also evaluated as a meat protein extender. Textural profile and torsional gelometry analyses of the cooked meat gels showed TGase alone significantly (p < 0.05) increased gel texture, especially for those made from PSE meat. However, cook yield of the meat gels was compromised possibly due to steric effects. Addition of pea protein isolate alone improved cook yield and gel texture, especially for the gels made from PSE meat. The combination of TGase and pea protein produced the strongest meat gels, while maintaining a similar cook yield to the control. SDS-PAGE showed the disappearance of several protein bands contributed from the meat or pea protein with TGase addition, indicating that these likely were crosslinked and too large to enter the gel. Dynamic rheological analysis revealed TGase altered the viscoelastic properties of the meat or meat-pea protein mixtures and produced more elastic gels on cooling.<p>This research indicated proteolysis had a dramatic impact on textural properties of turkey breast meat gels. Crosslinking of proteins catalyzed by TGase significantly improved gel texture, especially for the gels made from PSE meat. However, TGase-assisted crosslinking of proteins resulted in greater cooking losses unless an extender/adjunct such as pea protein was added. PSE meat gel protein crosslinking protein degradation water holding capacity textural property
3	Extensin Peroxidase Identification and Characterization in <i>Solanum lycopersicum</i> Dong, Wen 24 August 2015 (has links) No description available. Biochemistry Plant Biology Hydroxyproline-rich glycoproteins plant cell wall extensin peroxidase protein crosslinking
4	The Development and Application of Mass Spectrometry-based Structural Proteomic Approaches to Study Protein Structure and Interactions Makepeace, Karl A.T. 26 August 2022 (has links) Proteins and their intricate network of interactions are fundamental to many molecular processes that govern life. Mass spectrometry-based structural proteomics represents a powerful set of techniques for characterizing protein structures and interactions. The last decade has witnessed a large-scale adoption in the application of these techniques toward solving a variety of biological questions. Addressing these questions has often been coincident with the further development of these techniques. Insight into the structures of individual proteins and their interactions with other proteins in a proteome-wide context has been made possible by recent developments in the relatively new field of chemical crosslinking combined with mass spectrometry. In these experiments crosslinking reagents are used to capture protein-protein interactions by forming covalent linkages between proximal amino acid residues. The crosslinked proteins are then enzymatically digested into peptides, and the covalently-coupled crosslinked peptides are identified by mass spectrometry. These identified crosslinked peptides thus provide evidence of interacting regions within or between proteins. In this dissertation the development of tools and methods that facilitate this powerful technique are described. The primary arc of this work follows the development and application of mass spectrometry-based approaches for the identification of protein crosslinks ranging from those which exist endogenously to those which are introduced synthetically. Firstly, the development of a novel strategy for comprehensive determination of naturally occurring protein crosslinks in the form of disulfide bonds is described. Secondly, the application of crosslinking reagents to create synthetic crosslinks in proteins coupled with molecular dynamics simulations is explored in order to structurally characterize the intrinsically disordered tau protein. Thirdly, improvements to a crosslinking-mass spectrometry method for defining a protein-protein interactome in a complex sample is developed. Altogether, these described approaches represent a toolset to allow researchers to access information about protein structure and interactions. / Graduate Mass Spectrometry Structural Proteomics Crosslinking Cross-linking Disulfide bonds Proteomics Tau Mitochondria Method development Molecular dynamics Protein chemistry Protein crosslinking Protein cross-linking Shotgun proteomics Bottom-up proteomics Data-dependent acquisition DDA Protein-protein interactome Interactome Interactomics Proteinase K Trypsin Higher-order crosslinking Machine learning Feature engineering Yeast Yeast mitochondria Algorithms Data analysis Surface modification Molecular modelling Non-specific digest Structural mass spectrometry Structural biology Biochemistry LC-MS

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