Proteolysis is one of the most important biochemical reactions during cheese ripening.Studies on the secondary structure of proteins during ripening would be helpful for characterizing protein changes for assessing ch...Proteolysis is one of the most important biochemical reactions during cheese ripening.Studies on the secondary structure of proteins during ripening would be helpful for characterizing protein changes for assessing cheese quality.Fourier transform infrared spectroscopy(FTIR),with self-deconvolution,second derivative analysis and band curve-fitting,was used to characterize the secondary structure of proteins in Cheddar cheese during ripening.The spectra of the amide I region showed great similarity,while the relative contents of the secondary structures underwent a series of changes.As ripening progressed,the α-helix content decreased and the β-sheet content increased.This structural shift was attributed to the strengthening of hydrogen bonds that resulted from hydrolysis of caseins.In summary,FTIR could provide the basis for rapid characterization of cheese that is undergoing ripening.展开更多
Aim:To determine the secondary structure of insulin encapsulated within liposome.Methods:The secondary structure of native insulin,mixture of insulin with liposome(sample I) and insulin encapsulated within liposome(sa...Aim:To determine the secondary structure of insulin encapsulated within liposome.Methods:The secondary structure of native insulin,mixture of insulin with liposome(sample I) and insulin encapsulated within liposome(sample Ⅱ) were determined by FTIR(Fourier Transform Infrared) spectroscopy.Results:The secondary structure of insulin encspsulated within liposome(Ⅱ） are similar with the secondary structure of native insulin.The difference existed in the amount of α-helices (from 36% of insulin to 31% of sample Ⅱ）and β-sheet(from 48% of insulin to 51% of sample Ⅱ).The content of α-helices and β-sheet of insulin in sample I was found to be very close to that of sample Ⅱ.The results revealed that the insulin encapsulated within liposome possibly spread on the surface of liposome,without inserting into the liposome membrane.Coclusion:The secondary structure of insulin encapsulated within liposome is similar with the native insulin.展开更多
The compositions of the secondary structures of protein in the human breast normal, hyperplasia, fibroadenoma and invasive ductal carcinoma tissues have been estimated from the Fourier self deconvolved spectra, the se...The compositions of the secondary structures of protein in the human breast normal, hyperplasia, fibroadenoma and invasive ductal carcinoma tissues have been estimated from the Fourier self deconvolved spectra, the second derivative spectra and the curve-fitting analysis of the amide I bands in their spectra. Some parameters of the secondary structures of proteins in these 4 types of tissues are significantly different and located in separate ranges.展开更多
Aminoacylase is a dimeric metal enzyme containing one Zn<sup>2+</sup>-ion per subunit of active site.It is essential for the activity of enzyme.Fourier transform-infrared spectroscopy has been used for the...Aminoacylase is a dimeric metal enzyme containing one Zn<sup>2+</sup>-ion per subunit of active site.It is essential for the activity of enzyme.Fourier transform-infrared spectroscopy has been used for the studyon the secondary structure of holo-enzyme and ago-enzyme of aminoaeylase from pig kidney.Resolution en-hancement of the amide I secondary structure-sensitive overlapped component bands has been achieved bymeans of the Fourier self-deconvolution and the Fourier derivation.The effect of Zn<sup>2+</sup>-ion on the secondarystructure of aminoacylase was observed clearly.After the removal of Zn<sup>2+</sup>in aminoacylase,the extent of theordered structure was decreased markedly.It suggests that the conformation st or near the active site ofaminoacylase contains more ordered structures,and the presence of Zn<sup>2+</sup>helps to keep the conformation ofthe active site required for the catalysis of the enzyme.展开更多
基金financially supported by Beijing Municipal Commission of Education Co-Constructed Programand Chinese Universities Scientific Fund(2009-4-25)
文摘Proteolysis is one of the most important biochemical reactions during cheese ripening.Studies on the secondary structure of proteins during ripening would be helpful for characterizing protein changes for assessing cheese quality.Fourier transform infrared spectroscopy(FTIR),with self-deconvolution,second derivative analysis and band curve-fitting,was used to characterize the secondary structure of proteins in Cheddar cheese during ripening.The spectra of the amide I region showed great similarity,while the relative contents of the secondary structures underwent a series of changes.As ripening progressed,the α-helix content decreased and the β-sheet content increased.This structural shift was attributed to the strengthening of hydrogen bonds that resulted from hydrolysis of caseins.In summary,FTIR could provide the basis for rapid characterization of cheese that is undergoing ripening.
文摘Aim:To determine the secondary structure of insulin encapsulated within liposome.Methods:The secondary structure of native insulin,mixture of insulin with liposome(sample I) and insulin encapsulated within liposome(sample Ⅱ) were determined by FTIR(Fourier Transform Infrared) spectroscopy.Results:The secondary structure of insulin encspsulated within liposome(Ⅱ） are similar with the secondary structure of native insulin.The difference existed in the amount of α-helices (from 36% of insulin to 31% of sample Ⅱ）and β-sheet(from 48% of insulin to 51% of sample Ⅱ).The content of α-helices and β-sheet of insulin in sample I was found to be very close to that of sample Ⅱ.The results revealed that the insulin encapsulated within liposome possibly spread on the surface of liposome,without inserting into the liposome membrane.Coclusion:The secondary structure of insulin encapsulated within liposome is similar with the native insulin.
文摘The compositions of the secondary structures of protein in the human breast normal, hyperplasia, fibroadenoma and invasive ductal carcinoma tissues have been estimated from the Fourier self deconvolved spectra, the second derivative spectra and the curve-fitting analysis of the amide I bands in their spectra. Some parameters of the secondary structures of proteins in these 4 types of tissues are significantly different and located in separate ranges.
文摘Aminoacylase is a dimeric metal enzyme containing one Zn<sup>2+</sup>-ion per subunit of active site.It is essential for the activity of enzyme.Fourier transform-infrared spectroscopy has been used for the studyon the secondary structure of holo-enzyme and ago-enzyme of aminoaeylase from pig kidney.Resolution en-hancement of the amide I secondary structure-sensitive overlapped component bands has been achieved bymeans of the Fourier self-deconvolution and the Fourier derivation.The effect of Zn<sup>2+</sup>-ion on the secondarystructure of aminoacylase was observed clearly.After the removal of Zn<sup>2+</sup>in aminoacylase,the extent of theordered structure was decreased markedly.It suggests that the conformation st or near the active site ofaminoacylase contains more ordered structures,and the presence of Zn<sup>2+</sup>helps to keep the conformation ofthe active site required for the catalysis of the enzyme.
