The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform
Chulhee Kang - One of the best experts on this subject based on the ideXlab platform.
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comparing skeletal and cardiac calsequestrin structures and their calcium binding a proposed mechanism for coupled calcium binding and Protein Polymerization
Journal of Biological Chemistry, 2004Co-Authors: Hajeung Park, I Y Park, Buhyun Youn, K Fields, A K Dunker, Chulhee KangAbstract:Abstract Calsequestrin, the major calcium storage Protein of both cardiac and skeletal muscle, binds and releases large numbers of Ca2+ ions for each contraction and relaxation cycle. Here we show that two crystal structures for skeletal and cardiac calsequestrin are nearly superimposable not only for their subunits but also their front-to-front-type dimers. Ca2+ binding curves were measured using atomic absorption spectroscopy. This method enables highly accurate measurements even for Ca2+ bound to polymerized Protein. The binding curves for both skeletal and cardiac calsequestrin were complex, with binding increases that correlated with Protein dimerization, tetramerization, and oligomerization. The Ca2+ binding capacities of skeletal and cardiac calsequestrin are directly compared for the first time, with ∼80 Ca2+ ions bound per skeletal calsequestrin and ∼60 Ca2+ ions per cardiac calsequestrin, as compared with net charges for these molecules of -80 and -69, respectively. Deleting the negatively charged and disordered C-terminal 27 amino acids of cardiac calsequestrin results in a 50% reduction of its calcium binding capacity and a loss of Ca2+-dependent tetramer formation. Based on the crystal structures of rabbit skeletal muscle calsequestrin and canine cardiac calsequestrin, Ca2+ binding capacity data, and previous light-scattering data, a mechanism of Ca2+ binding coupled with Polymerization is proposed.
Silvia C Kivatinitz - One of the best experts on this subject based on the ideXlab platform.
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evaluation of milk powder quality by Protein oxidative modifications12
Journal of Dairy Science, 2013Co-Authors: Dana Scheidegger, Paola Marcela Radici, Victor A Vergararoig, Noelia S Bosio, Silvia F Pesce, Rolando Pascual Pecora, Jose C P Romano, Silvia C KivatinitzAbstract:Abstract The objective of the present research was to evaluate commercially available milk powders according to their Protein oxidative modifications and antioxidant capacity, and to evaluate if these characteristics are related to physical quality parameters such as dispersibility or stability during storage. Fifteen commercially processed spray-dried milk powders were evaluated: 6 whole milk powders (WMP), 4 skim milk powders (SMP), and 5 infant formula powders (IFP). Protein oxidative status was measured as Protein carbonyl (PC) content, dityrosine content, and extent of Protein Polymerization. The level of PC was slightly lower in SMP than in WMP, whereas IFP had more than twice as much PC as WMP (2.8 ± 0.4, 2.1 ± 0.2, and 6.5 ± 1.3 nmol/mg of Protein for WMP, SMP, and IFP, respectively). No differences were detected in dityrosine accumulation. Although all the possible pairs of parameters were tested for correlations, we found that 4 parameters were linked: PC, whey content, Protein aggregate level, and dispersibility. After 9 mo of storage at −20°C or room temperature, all milk samples were analyzed to evaluate changes in Protein oxidative status (PC, dityrosine, and Protein integrity) and related parameters. Compared with the initial condition, PC increased in all tested samples after 9 mo of storage at −20°C or at room temperature. Stored milk powders had increased PC and decreased dispersibility compared with prestorage levels. Our results highlight the importance of Protein oxidative status in milk powder and its relationship to other related quality parameters, such as Protein integrity and dispersibility. Our findings suggest that the understanding of such relationships could help in developing quality differentiation for different types of milk powders in the product market.
Eva Johansson - One of the best experts on this subject based on the ideXlab platform.
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unraveling the structural puzzle of the giant glutenin polymer an interplay between Protein Polymerization nanomorphology and functional properties in bioplastic films
ACS omega, 2018Co-Authors: Faiza Rasheed, Tomas S Plivelic, Ramune Kuktaite, Mikael S Hedenqvist, Eva JohanssonAbstract:A combination of genotype, cultivation environment, and Protein separation procedure was used to modify the nanoscale morphology, Polymerization, and chemical structure of glutenin Proteins from wh ...
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the impact of newly produced Protein and dietary fiber rich fractions of yellow pea pisum sativum l on the structure and mechanical properties of pasta like sheets
Food Research International, 2018Co-Authors: Faraz Muneer, Tomas S Plivelic, Mikael S Hedenqvist, Eva Johansson, Keld Ejdrup Markedal, Iben Lykke Petersen, Jens Christian Sorensen, Ramune KuktaiteAbstract:Two fractions from pea (Pisum sativum L.), Protein isolate (PPI) and dietary fiber (PF), were newly produced by extraction-fractionation method and characterized in terms of particle size distribution and structural morphology using SEM. The newly produced PPI and PF fractions were processed into pasta-like sheets with varying Protein to fiber ratios (100/0, 90/10, 80/20, 70/30 and 50/50, respectively) using high temperature compression molding. We studied Protein Polymerization, molecular structure and Protein-fiber interactions, as well as mechanical performance and cooking characteristics of processed PPI-PF blends. Bi-modal particle size distribution and chemical composition of the PPI and PF fractions influenced significantly the physicochemical properties of the pasta-like sheets. Polymerization was most pronounced for the 100 PPI, 90/10 and 80/20 PPI-PF samples as studied by SE-HPLC, and Polymerization decreased with addition of the PF fraction. The mechanical properties, as strength and extensibility, were likewise the highest for the 100 PPI and 90/10 PPI-PF blends, while the E-modulus was similar for all the studied blends (around 38 MPa). The extensibility decreased with the increasing amount of PF in the blend. The highest amounts of β-sheets were found in the pasta-like sheets with high amounts of PPI (100, 90 and 80%), by FT-IR. An increase in PF fraction in the blend, resulted into the high amounts of unordered structures as observed by FT-IR, as well as in an increase in the molecular scattering distances observed by SAXS. The water uptake increased and cooking loss decreased with increased proportions of the PF fraction, and the consistency of 10 min cooked pasta-like sheets were alike al dente texture. The new knowledge obtained in this study on the use of extraction-fractionation method to produce novel PPI and PF fractions for developing innovative high nutritious food can be of a great importance. The obtained knowledge on the pea Protein and fiber processing behaviour could greatly contribute to a better control of functional properties of various temperature-processed products from yellow pea.
Ramune Kuktaite - One of the best experts on this subject based on the ideXlab platform.
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unraveling the structural puzzle of the giant glutenin polymer an interplay between Protein Polymerization nanomorphology and functional properties in bioplastic films
ACS omega, 2018Co-Authors: Faiza Rasheed, Tomas S Plivelic, Ramune Kuktaite, Mikael S Hedenqvist, Eva JohanssonAbstract:A combination of genotype, cultivation environment, and Protein separation procedure was used to modify the nanoscale morphology, Polymerization, and chemical structure of glutenin Proteins from wh ...
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the impact of newly produced Protein and dietary fiber rich fractions of yellow pea pisum sativum l on the structure and mechanical properties of pasta like sheets
Food Research International, 2018Co-Authors: Faraz Muneer, Tomas S Plivelic, Mikael S Hedenqvist, Eva Johansson, Keld Ejdrup Markedal, Iben Lykke Petersen, Jens Christian Sorensen, Ramune KuktaiteAbstract:Two fractions from pea (Pisum sativum L.), Protein isolate (PPI) and dietary fiber (PF), were newly produced by extraction-fractionation method and characterized in terms of particle size distribution and structural morphology using SEM. The newly produced PPI and PF fractions were processed into pasta-like sheets with varying Protein to fiber ratios (100/0, 90/10, 80/20, 70/30 and 50/50, respectively) using high temperature compression molding. We studied Protein Polymerization, molecular structure and Protein-fiber interactions, as well as mechanical performance and cooking characteristics of processed PPI-PF blends. Bi-modal particle size distribution and chemical composition of the PPI and PF fractions influenced significantly the physicochemical properties of the pasta-like sheets. Polymerization was most pronounced for the 100 PPI, 90/10 and 80/20 PPI-PF samples as studied by SE-HPLC, and Polymerization decreased with addition of the PF fraction. The mechanical properties, as strength and extensibility, were likewise the highest for the 100 PPI and 90/10 PPI-PF blends, while the E-modulus was similar for all the studied blends (around 38 MPa). The extensibility decreased with the increasing amount of PF in the blend. The highest amounts of β-sheets were found in the pasta-like sheets with high amounts of PPI (100, 90 and 80%), by FT-IR. An increase in PF fraction in the blend, resulted into the high amounts of unordered structures as observed by FT-IR, as well as in an increase in the molecular scattering distances observed by SAXS. The water uptake increased and cooking loss decreased with increased proportions of the PF fraction, and the consistency of 10 min cooked pasta-like sheets were alike al dente texture. The new knowledge obtained in this study on the use of extraction-fractionation method to produce novel PPI and PF fractions for developing innovative high nutritious food can be of a great importance. The obtained knowledge on the pea Protein and fiber processing behaviour could greatly contribute to a better control of functional properties of various temperature-processed products from yellow pea.
Hajeung Park - One of the best experts on this subject based on the ideXlab platform.
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comparing skeletal and cardiac calsequestrin structures and their calcium binding a proposed mechanism for coupled calcium binding and Protein Polymerization
Journal of Biological Chemistry, 2004Co-Authors: Hajeung Park, I Y Park, Buhyun Youn, K Fields, A K Dunker, Chulhee KangAbstract:Abstract Calsequestrin, the major calcium storage Protein of both cardiac and skeletal muscle, binds and releases large numbers of Ca2+ ions for each contraction and relaxation cycle. Here we show that two crystal structures for skeletal and cardiac calsequestrin are nearly superimposable not only for their subunits but also their front-to-front-type dimers. Ca2+ binding curves were measured using atomic absorption spectroscopy. This method enables highly accurate measurements even for Ca2+ bound to polymerized Protein. The binding curves for both skeletal and cardiac calsequestrin were complex, with binding increases that correlated with Protein dimerization, tetramerization, and oligomerization. The Ca2+ binding capacities of skeletal and cardiac calsequestrin are directly compared for the first time, with ∼80 Ca2+ ions bound per skeletal calsequestrin and ∼60 Ca2+ ions per cardiac calsequestrin, as compared with net charges for these molecules of -80 and -69, respectively. Deleting the negatively charged and disordered C-terminal 27 amino acids of cardiac calsequestrin results in a 50% reduction of its calcium binding capacity and a loss of Ca2+-dependent tetramer formation. Based on the crystal structures of rabbit skeletal muscle calsequestrin and canine cardiac calsequestrin, Ca2+ binding capacity data, and previous light-scattering data, a mechanism of Ca2+ binding coupled with Polymerization is proposed.
