ABSTRACT
Objective@#To optimize the enzymatic digestion conditions of trypsin, so as to improve the testing capacity of mass spectrometry for shrimp allergens.@*Methods@#The enzymatic digestion test was carried out by response surface methodology for optimizing pH, temperature and time. After enzymatic hydrolysis, the peptides were separated by chromatography and determined by high-resolution mass spectrometry with Q-orbitrap. The allergen protein was identified and quantified by UniProt database and MaxQuant software.@*Results@#Two allergen proteins, tropomyosin and arginine kinase, were isolated from shrimp, and their intensities ranged from 100.2×106 to 436.5×106. Response surface analysis showed that when the digestion time was 4.29 hours, the temperature was 44.15 ℃ and pH value was 6.55, the maximal intensity of the allergen proteins was 457.48×106. The experiment was validated with the digestion time of 4.2 h, pH value of 6.5, and temperature of 44 ℃, then resulted in the average intensity of 448.1×106. The deviation from the predicted value was 2.1%.@*Conclusions@#The conditions of enzymatic digestion can be optimized by response surface methodology. The enzyme may have the best performance with the pH value of 6.5, temperature of 44 ℃ and digestion time of 4.2 hours.
ABSTRACT
Objective@#To establish the ultra-high performance liquid chromatography coupled with quadrupole orbitrap mass spectrometry ( UPLC-Q-Orbitrap-MS ) for the analysis of allergen protein in Macrobrachium. @*Methods@#Based on the strategy of bottom-up protein analysis, the proteins in Macrobrachium samples were extracted by Tris-HCl, digested by trypsin at 40 ℃ for 6 hours, separated by chromatography, and analyzed by Q-Orbitrap-MS spectrometry ( Full MS/dd-MS2, TopN=10 ) . Allergen proteins were identified with UniProt protein database and Proteome Discoverer software. @*Results@# Four kinds of allergen proteins were obtained, which were tropomyosin, arginine kinase, sarcoplasmic calcium binding protein and hemocyanin. The coverage rates of peptides in proteins were 53%, 36%, 12% and 12%, respectively. Post translation modifications were methylation of aspartic acid (D), deacylylation of aspartic acid ( N ) , glutamyl ammonia ( Q ) and oxidation of methionine ( M ) .@*Conclusions@#The UPLC-Q-Orbitrap-MS can identified abundant peptide and fragment information with high sensitivity and resolution, which provides a technical support for the analysis of shrimp allergens.
ABSTRACT
OBJECTIVES: Alcohol for intercostal neuralgia may induce severe injection pain. Although nerve block provided partial pain relief, alcohol might be diluted, and the curative effect decreased when the local anesthetic and alcohol were given at the same point. Therefore, we observed the modified method for intercostal neuralgia, a Two-point method, in which the local anesthetic and alcohol were given at different sites. METHOD: Thirty patients diagnosed with intercostal neuralgia were divided into 2 groups: Single-point group and Two-point group. In the Single-point group, alcohol and local anesthetic were injected at the same point, named the "lesion point", which was the lower edge of ribs and 5 cm away from the midline of the spinous process. In the Two-point group, alcohol was injected at the lesion point, whereas the local anesthetic was administered at the "anesthesia point", which was 3 cm away from the midline of spinous process. RESULTS: After alcohol injection, visual analog scale (VAS) in the Two-point group was lower than the Single-point group, and the satisfaction ratio of patients in the Two-point group was higher (p<0.05). The degree of numbness in the Two-point group was greater than the Single-point group at 1 month and 3 months after operation (p<0.05). However, the long-term effects did not differ. CONCLUSIONS: Local anesthetic was given upstream of the point where alcohol was administered, was a feasible and safe method to relieve pain during the operation, and improved the satisfaction of the patients and curative effect.