Rationale: To investigate the fragmentations in the negative-ion electrospray mass spectra of peptides containing tyrosine sulfate.
Methods: Possible fragmentation mechanisms were explored using a Waters QTOF2 tandem mass spectrometer in concert with calculations at the CAM-B3LYP/6-311++g(d,p) level of theory.
Results: The major negative ion formed in the ESI-MS of peptides containing tyrosine sulfate is [(M-H)-SO3](-) and this process normally yields the base peak of the spectrum. The basic backbone cleavages of [(M-H)-SO3](-) allowed the sequence of the peptide to be determined. Rearrangement reactions involving the formation of HOSO3(-) and [(M-H)-H2SO4](-) yielded minor peaks with relative abundances ≤ 10% and ≤ 2%, respectively.
Conclusions: The mass spectra of the [M-H](-) and [(M-H)-SO3](-) anions of peptides containing tyrosine sulfate allowed the position of the tyrosine sulfate group to be determined, together with the amino acid sequence of the peptide.
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http://dx.doi.org/10.1002/rcm.6547 | DOI Listing |
T-cell receptor recognition of cognate peptide-MHC leads to the formation of signalling domains and the immunological synapse. Because of the close membrane apposition, there is rapid exclusion of CD45, and therefore LCK activation. Much less is known about whether spatial regulation of the intracellular face dictates LCK activity and TCR signal transduction.
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January 2025
Yalova University, Faculty of Medicine, Department of Medical Biochemistry, AD - Yalova, Turkey.
Objective: Calorie restriction and exercise are commonly used first interventions to prevent the progression of prediabetes and alleviate the symptoms of type 2 diabetes. Our study was designed to determine the effect of the energy deficit caused by long-term (12-week) calorie restriction and exercise programs on appetite responses in obese individuals with prediabetes and type 2 diabetes.
Methods: Calorie restriction and exercise programs appropriate for age, gender, and work environment were applied to 22 individuals with prediabetes and 22 with type 2 diabetes participating in the study for a period of 12 weeks.
Langmuir
January 2025
Department of Chemistry, University of North Bengal, Raja Rammohanpur, Siliguri 734013, West Bengal, India.
Self-assembly of amino acids and short-peptide derivatives attracted significant curiosity worldwide due to their unique self-assembly process and wide variety of applications. Amino acid is considered one of the important synthons in supramolecular chemistry. Self-assembly processes and applications of unfunctionalized native amino acids have been less reported in the literature.
View Article and Find Full Text PDFJ Mater Chem B
January 2025
State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Quality and Healthy of Tianjin, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin, 300457, P. R. China.
In an antioxidant peptide study, the number and position of active amino acid sites, as well as the peptides' conformation, are found to be crucial for scavenging hydroxyl radicals (˙OH). Herein, ˙the OH scavenging activity of tilapia pentapeptide (P1, YGDQY) and its analogs including P2 (YYYGDQY), P3 (YYGDQYY) and P4 (YYGPDQYY) was investigated. The results showed that the tyrosine's amount, location and the peptides' conformation played important roles in determining peptides' scavenging activity (34.
View Article and Find Full Text PDFACS Chem Neurosci
January 2025
School of Pharmacy, University of Wisconsin─Madison, Madison, Wisconsin 53705, United States.
Addiction to psychostimulants, including cocaine, causes widespread morbidity and mortality and is a major threat to global public health. Currently, no pharmacotherapies can successfully treat psychostimulant addiction. The neuroactive effects of cocaine and other psychostimulants have been studied extensively with respect to their modulation of monoamine systems (particularly dopamine); effects on neuropeptide systems have received less attention.
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