Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Ar...Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Arsenazo M itself. The apparent molar absorptivity of the BSA-Arsenazo M complex is 3.21105 Lmol-1cm-1. The linear ranges for protein determination are wide (at least 0-100 mg/mL).展开更多
The application of 5'-nitrosalicylfluorone (5'-NSF)-molybdenum(VI) complex as a spectroscopic probe was studied. In the buffer medium of HOAc-NaOAc at 3.45 and in the presence of PVA 124 microemulsion, 5'-...The application of 5'-nitrosalicylfluorone (5'-NSF)-molybdenum(VI) complex as a spectroscopic probe was studied. In the buffer medium of HOAc-NaOAc at 3.45 and in the presence of PVA 124 microemulsion, 5'-NSF-Mo(VI) complex combines protein rapidly to form a stable compound, leading to an absorbance decrease at 525 nm of 5'-NSF-Mo(VI) complex. According to this change, microdetermination of protein has been described. Bovine serum albumin (BSA) could be determined in the linear range of 0—16 g昺L-1 with the detection limit of 11 ngmL-1. Many amino acid and metal ions studied do not interfere with the assay. The method possesses high sensitivity as well as high selectivity. It can be used to determine protein in human urine and milk powder successfully. The relative standard deviations are in all instances less than 4.7%, and the recoveries are between 97.6% and 106.0%. Moreover, the binding number of BSA with the complex, which is determined by using molar ratio, Rosenthanl graphic and slope ratio methods, is in good agreement with each other.展开更多
The application of phenylfluorone (PF)-Mo(VI) complex as a spectroscopic probe is studied. In the presence of OP microemulsion at pH 3.04, PF-Mo(Ⅵ) complex combines protein rapidly to form a stable compound and the a...The application of phenylfluorone (PF)-Mo(VI) complex as a spectroscopic probe is studied. In the presence of OP microemulsion at pH 3.04, PF-Mo(Ⅵ) complex combines protein rapidly to form a stable compound and the absorbance at 527 nm is in proportion to the concentration of protein in the range 0-16 μg mL-1 for bovine serum albumin (BSA). OP microemuslion media is introduced into protein determination, it has increased markedly the sensitivity of the system. The molar absorption coefficient was 5.98×l06 L mol-1 cm-1 for BSA. The assay, with sensitivity, simplicity and tolerance to many foreign substances, is applied to the determination of protein in samples with satisfactory results. Moreover, the binding number of BSA with the complex, which is determined by molar ratio and slope ratio methods, is in good agreement.展开更多
A new method for the analysis of protein colloidal diameter has been developed using three existing protein concentration quantification techniques, absorption at 280 nm, colloidal gold assay, and DC protein assay. Pr...A new method for the analysis of protein colloidal diameter has been developed using three existing protein concentration quantification techniques, absorption at 280 nm, colloidal gold assay, and DC protein assay. Protein colloids are formed in the process of aggregation and are thought to be intermediates in protein self-assembly and formation of amyloid fiber. Deposition of the protein fibers in tissues leads to numerous human diseases including Alzheimer’s. Lysozyme was incubated at pH 2.0, 55°C, an environment conducive to amyloid fiber formation. The protein colloids present in the supernatant of the samples after centrifugation were studied over a time course of 30 days. The OD 280 assay detects total protein concentration based on absorption of radiation in the near UV. The colloidal gold assay and DC protein assay only measure colloidal sphere surface protein concentration. Due to the surface plasmon resonance, the light absorption spectrum changes when proteins bind to colloidal gold particles. Using the measured protein concentration on the surface of protein colloids along with the total measured protein concentration in the entire protein colloidal spheres, an interior protein concentration for all colloids is obtained. The protein colloidal sphere size can be calculated by using the ratio between the interior protein concentration and total protein concentration. Results indicate that the colloidal gold assay, DC protein assay, and OD 280 assay can be used to quantify the size of the protein colloids. The colloidal gold assay and DC protein assay are both independently effective in analysis of surface protein concentration in protein colloids. The DC protein assay was found to be much quicker in data production as it only requires 15 minutes of incubation time. The DC protein assay was also more reliable than the colloidal gold assay in accuracy and precision of results.展开更多
文摘Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Arsenazo M itself. The apparent molar absorptivity of the BSA-Arsenazo M complex is 3.21105 Lmol-1cm-1. The linear ranges for protein determination are wide (at least 0-100 mg/mL).
基金Project supported by the Natural Science Foundation of Shandong Province (No. Y2000B09) and the Science and Technology Programme of Shandong Province (No. 03C05).
文摘The application of 5'-nitrosalicylfluorone (5'-NSF)-molybdenum(VI) complex as a spectroscopic probe was studied. In the buffer medium of HOAc-NaOAc at 3.45 and in the presence of PVA 124 microemulsion, 5'-NSF-Mo(VI) complex combines protein rapidly to form a stable compound, leading to an absorbance decrease at 525 nm of 5'-NSF-Mo(VI) complex. According to this change, microdetermination of protein has been described. Bovine serum albumin (BSA) could be determined in the linear range of 0—16 g昺L-1 with the detection limit of 11 ngmL-1. Many amino acid and metal ions studied do not interfere with the assay. The method possesses high sensitivity as well as high selectivity. It can be used to determine protein in human urine and milk powder successfully. The relative standard deviations are in all instances less than 4.7%, and the recoveries are between 97.6% and 106.0%. Moreover, the binding number of BSA with the complex, which is determined by using molar ratio, Rosenthanl graphic and slope ratio methods, is in good agreement with each other.
文摘The application of phenylfluorone (PF)-Mo(VI) complex as a spectroscopic probe is studied. In the presence of OP microemulsion at pH 3.04, PF-Mo(Ⅵ) complex combines protein rapidly to form a stable compound and the absorbance at 527 nm is in proportion to the concentration of protein in the range 0-16 μg mL-1 for bovine serum albumin (BSA). OP microemuslion media is introduced into protein determination, it has increased markedly the sensitivity of the system. The molar absorption coefficient was 5.98×l06 L mol-1 cm-1 for BSA. The assay, with sensitivity, simplicity and tolerance to many foreign substances, is applied to the determination of protein in samples with satisfactory results. Moreover, the binding number of BSA with the complex, which is determined by molar ratio and slope ratio methods, is in good agreement.
文摘A new method for the analysis of protein colloidal diameter has been developed using three existing protein concentration quantification techniques, absorption at 280 nm, colloidal gold assay, and DC protein assay. Protein colloids are formed in the process of aggregation and are thought to be intermediates in protein self-assembly and formation of amyloid fiber. Deposition of the protein fibers in tissues leads to numerous human diseases including Alzheimer’s. Lysozyme was incubated at pH 2.0, 55°C, an environment conducive to amyloid fiber formation. The protein colloids present in the supernatant of the samples after centrifugation were studied over a time course of 30 days. The OD 280 assay detects total protein concentration based on absorption of radiation in the near UV. The colloidal gold assay and DC protein assay only measure colloidal sphere surface protein concentration. Due to the surface plasmon resonance, the light absorption spectrum changes when proteins bind to colloidal gold particles. Using the measured protein concentration on the surface of protein colloids along with the total measured protein concentration in the entire protein colloidal spheres, an interior protein concentration for all colloids is obtained. The protein colloidal sphere size can be calculated by using the ratio between the interior protein concentration and total protein concentration. Results indicate that the colloidal gold assay, DC protein assay, and OD 280 assay can be used to quantify the size of the protein colloids. The colloidal gold assay and DC protein assay are both independently effective in analysis of surface protein concentration in protein colloids. The DC protein assay was found to be much quicker in data production as it only requires 15 minutes of incubation time. The DC protein assay was also more reliable than the colloidal gold assay in accuracy and precision of results.
