High-Pressure FTIR Study of the Stability of Horseradish Peroxidase. Effect of Heme Substitution, Ligand Binding, Ca++Removal, and Reduction of the Disulfide Bonds†

Biochemistry ◽  
2003 ◽  
Vol 42 (2) ◽  
pp. 553-561 ◽  
Author(s):  
L. Smeller ◽  
F. Meersman ◽  
J. Fidy ◽  
K. Heremans
Keyword(s):  
High Pressure ◽  
Horseradish Peroxidase ◽  
Ligand Binding ◽  
Disulfide Bonds ◽  
Ftir Study ◽  
The Stability

Development and evaluation of an immunoenzymometric assay for the chicken progesterone receptor

1991 ◽  
Vol 129 (2) ◽  
pp. 189-196 ◽  
Author(s):  
M. K. Bläuer ◽  
P. J. Tuohimaa ◽  
P. J. Vilja
Keyword(s):  
Monoclonal Antibodies ◽  
Small Intestine ◽  
Horseradish Peroxidase ◽  
Progesterone Receptor ◽  
Ligand Binding ◽  
Binding Assay ◽  
Ligand Binding Assay ◽  
Coefficients Of Variation ◽  
First Time ◽  
Determination Range

ABSTRACT A specific and sensitive immunoenzymometric assay (IEMA) was developed for measuring the quantity of chicken progesterone receptor (PR) in tissue cytosol. The assay uses two monoclonal antibodies to the PR. One is used to capture the PR. The second (labelled with biotin) reacts first with the captured receptor and subsequently with avidin-labelled horseradish peroxidase to provide an enzymatic end-point. The method has a determination range from 0·3 to 60 pmol/l. Intra- and interassay coefficients of variation were 3·7% and 9·0% respectively. The assay can be performed with equal results as a rapid (3 h) or an overnight procedure. The IEMA is convenient, especially for signal measurement and the calculation of results. No ultracentrifugation of samples is needed, since the IEMA can be performed on low-speed cytosol samples. Assay results correlated well (r = 0·927) with those obtained by the conventional ligand-binding assay used in our laboratory. Similar results were obtained with the IEMA and the ligand-binding assay after exposure of cytosol samples to increased temperatures: at 20 °C the PR remained stable for the 4-h period examined, whereas at 37 °C almost complete degradation of the PR was observed in 30 min. Being more than 100 times as sensitive as the ligand-binding assay, the IEMA enabled the quantification of PR for the first time in such tissues as the bursa and small intestine even of immature animals. Journal of Endocrinology (1991) 129, 189–196

scholarly journals Effect of food processing on the antioxidant activity of flavones from Polygonatum odoratum (Mill.) Druce

2021 ◽  
Vol 16 (1) ◽  
pp. 92-101
Author(s):  
Guanghui Xia ◽  
Xinhua Li ◽  
Zhen Zhang ◽  
Yuhang Jiang
Keyword(s):  
Antioxidant Activity ◽  
High Pressure ◽  
Food Processing ◽  
Yeast Fermentation ◽  
Pressure Treatment ◽  
Processing Methods ◽  
High Pressure Treatment ◽  
Effect Of Food ◽  
The Stability

Abstract Polygonatum odoratum (Mill.) Druce (POD) is a natural plant widely used for food and medicine, thanks to its rich content of a strong antioxidant agent called homoisoflavones. However, food processing methods could affect the stability of POD flavones, resulting in changes to their antioxidant activity. This study attempts to evaluate the antioxidant activity of POD flavones subject to different processing methods and determines which method could preserve the antioxidant activity of POD flavones. Therefore, flavones were extracted from POD samples, which had been treated separately with one of the four processing methods: extrusion, baking, high-pressure treatment, and yeast fermentation. After that, the antioxidant activity of the flavones was subject to in vivo tests in zebrafish embryos. The results show that yeast fermentation had the least disruption to the antioxidant activity of POD flavones, making it the most suitable food processing method for POD. By contrast, extrusion and high-pressure treatment both slightly weakened the antioxidant activity of the flavones and should be avoided in food processing. The research results provide a reference for the development and utilization of POD and the protection of its biological activity.

scholarly journals METHODS FOR THE STUDY OF SMALL PHAGOSOMES AND THEIR RELATIONSHIP TO LYSOSOMES WITH HORSERADISH PEROXIDASE AS A "MARKER PROTEIN"

1967 ◽  
Vol 15 (7) ◽  
pp. 375-380 ◽  
Author(s):  
WERNER STRAUS
Keyword(s):  
Acid Phosphatase ◽  
Low Temperature ◽  
Horseradish Peroxidase ◽  
Acid Medium ◽  
Tissue Section ◽  
Double Staining ◽  
Marker Protein ◽  
Polar Media ◽  
The Stability ◽  
Blue Reaction

Small phagosomes (micropinocytic vesicles and vacuoles) which had taken up injected horseradish peroxidase were identified by staining for peroxidase with benzidine and H2O2. Because of the small size of the granules and the possibility of artifacts, previously described procedures had to be modified in several respects. Prefixation of the tissue by perfusion at 37°C prevented artifacts of diffusion and adsorption of peroxidase. The blue product of the reaction of peroxidase with benzidine in the small phagosomes was preserved and fading to brown was prevented by cooling the tissue section to –10° to –15°C during its processing through polar media. The blue reaction product was stable as soon as the section was transferred to an apolar medium. Small phagosomes were visualized together with lysosomes and phago-lysosomes in the same cells by double staining for acid phosphatase and peroxidase in contrasting colors. The incubation for acid phosphatase was performed at 4°C since low temperature increased the stability of peroxidase in the acid medium. Factors which form the basis for other improvements of the procedure are discussed.

Roles of vanes in diffuser on stability of centrifugal compressor

2019 ◽  
Vol 233 (14) ◽  
pp. 5380-5392
Author(s):  
Wangzhi Zou ◽  
Xiao He ◽  
Wenchao Zhang ◽  
Zitian Niu ◽  
Xinqian Zheng
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Centrifugal Compressors ◽  
Compression System ◽  
The Stability ◽  
Rotating Instability

The stability considerations of centrifugal compressors become increasingly severe with the high pressure ratios, especially in aero-engines. Diffuser is the major subcomponent of centrifugal compressor, and its performance greatly influences the stability of compressor. This paper experimentally investigates the roles of vanes in diffuser on component instability and compression system instability. High pressure ratio centrifugal compressors with and without vanes in diffuser are tested and analyzed. Rig tests are carried out to obtain the compressor performance map. Dynamic pressure measurements and relevant Fourier analysis are performed to identify complex instability phenomena in the time domain and frequency domain, including rotating instability, stall, and surge. For component instability, vanes in diffuser are capable of suppressing the emergence of rotating stall in the diffuser at full speeds, but barely affect the characteristics of rotating instability in the impeller at low and middle speeds. For compression system instability, it is shown that the use of vanes in diffuser can effectively postpone the occurrence of compression system surge at full speeds. According to the experimental results and the one-dimensional flow theory, vanes in diffuser turn the diffuser pressure rise slope more negative and thus improve the stability of compressor stage, which means lower surge mass flow rate.

scholarly journals Equation of state studies at SILP by laser-driven shock waves

1996 ◽  
Vol 14 (2) ◽  
pp. 157-169 ◽  
Author(s):  
Yuan Gu ◽  
Sizu Fu ◽  
Jiang Wu ◽  
Songyu Yu ◽  
Yuanlong Ni ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Equation Of State ◽  
Shock Waves ◽  
Target Surface ◽  
Shock Adiabats ◽  
Pressure Shock ◽  
Aluminum Target ◽  
Laser Illumination ◽  
The Stability

The experimental progress of laser equation of state (EOS) studies at Shanghai Institute of Laser Plasma (SILP) is discussed in this paper. With a unique focal system, the uniformity of the laser illumination on the target surface is improved and a laser-driven shock wave with good spatial planarity is obtained. With an inclined aluminum target plane, the stability of shock waves are studied, and the corresponding thickness range of the target of laser-driven shock waves propagating steadily are given. The shock adiabats of Cu, Fe, SiO2 are experimentally measured. The pressure in the material is heightened remarkably with the flyer increasing pressure, and the effect of the increasing pressure is observed. Also, the high-pressure shock wave is produced and recorded in the experimentation of indirect laser-driven shock waves with the hohlraum target.

scholarly journals Evaluation of plasma, high-pressure and ultrasound processing on the stability of fructooligosaccharides

2016 ◽  
Vol 51 (9) ◽  
pp. 2034-2040 ◽  
Author(s):  
Elenilson G. Alves Filho ◽  
Patrick J. Cullen ◽  
Jesus M. Frias ◽  
Paula Bourke ◽  
Brijesh K. Tiwari ◽  
...  
Keyword(s):  
High Pressure ◽  
The Stability
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