It has been previously reported that, during denaturation of creatine kinase by guanidinium chlor... more It has been previously reported that, during denaturation of creatine kinase by guanidinium chloride (GdmCl) or urea [Tsou (1986), Trends Biochem. Sci. 11, 427-429], inactivation occurs before noticeable conformational change can be detected, and it is suggested that the conformation at the active site is more easily perturbed and hence more flexible than the molecule as a whole. In this study, the thiol and amino groups at or near the active site of creatine kinase are labelled with o-phthalaldehyde to form a fluorescent probe. Both the emission intensity and anisotropy decrease during denaturation indicating exposure of this probe and increased mobility of the active site. The above conformational changes take place together with enzyme inactivation at lower GdmCl concentrations than required to bring about intrinsic fluorescence changes of the enzyme. At the same GdmCl concentration, the rate of exposure of the probe is comparable with that of inactivation and is several orders o...
In poultry production, there is a lack of effective and convenient approaches to deliver bioactiv... more In poultry production, there is a lack of effective and convenient approaches to deliver bioactive compounds such as some essential oils, which have been proposed as alternatives to antibiotic growth promoters. The objective of this research was to develop a method for target delivery of essential oils in feed to the lower intestines of chickens. Carvacrol was used as a model essential oil, and 2 food-grade biopolymers, alginate and whey protein, were selected to encapsulate carvacrol in microparticles. The effects of a medium molecular weight alginate, a low molecular weight alginate (LBA), and whey protein concentrations on the properties of carvacrol-loaded microparticles were investigated using response surface methodology. The encapsulation efficiencies for all the tested formulations were ≥98% and carvacrol content in the dry microparticles was 72 ± 2% (wt/wt). The microparticles showed good gastric resistance and rapid intestinal release under simulated gastrointestinal condi...
It has been previously reported that, during denaturation of creatine kinase by guanidinium chlor... more It has been previously reported that, during denaturation of creatine kinase by guanidinium chloride (GdmCl) or urea [Tsou (1986), Trends Biochem. Sci. 11, 427-429], inactivation occurs before noticeable conformational change can be detected, and it is suggested that the conformation at the active site is more easily perturbed and hence more flexible than the molecule as a whole. In this study, the thiol and amino groups at or near the active site of creatine kinase are labelled with o-phthalaldehyde to form a fluorescent probe. Both the emission intensity and anisotropy decrease during denaturation indicating exposure of this probe and increased mobility of the active site. The above conformational changes take place together with enzyme inactivation at lower GdmCl concentrations than required to bring about intrinsic fluorescence changes of the enzyme. At the same GdmCl concentration, the rate of exposure of the probe is comparable with that of inactivation and is several orders o...
In poultry production, there is a lack of effective and convenient approaches to deliver bioactiv... more In poultry production, there is a lack of effective and convenient approaches to deliver bioactive compounds such as some essential oils, which have been proposed as alternatives to antibiotic growth promoters. The objective of this research was to develop a method for target delivery of essential oils in feed to the lower intestines of chickens. Carvacrol was used as a model essential oil, and 2 food-grade biopolymers, alginate and whey protein, were selected to encapsulate carvacrol in microparticles. The effects of a medium molecular weight alginate, a low molecular weight alginate (LBA), and whey protein concentrations on the properties of carvacrol-loaded microparticles were investigated using response surface methodology. The encapsulation efficiencies for all the tested formulations were ≥98% and carvacrol content in the dry microparticles was 72 ± 2% (wt/wt). The microparticles showed good gastric resistance and rapid intestinal release under simulated gastrointestinal condi...
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