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Zhang S, Ji Y, He Y, Dong J, Li H, Yu S. Effect of Environmental pH on the Mechanics of Chitin and Chitosan: A Single-Molecule Study. Polymers (Basel) 2024; 16:995. [PMID: 38611253 PMCID: PMC11014069 DOI: 10.3390/polym16070995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/14/2024] Open
Abstract
Chitin and chitosan are important structural macromolecules for most fungi and marine crustaceans. The functions and application areas of the two molecules are also adjacent beyond their similar molecular structure, such as tissue engineering and food safety where solution systems are involved. However, the elasticities of chitin and chitosan in solution lack comparison at the molecular level. In this study, the single-molecule elasticities of chitin and chitosan in different solutions are investigated via atomic force microscope (AFM) based single-molecule spectroscopy (SMFS). The results manifest that the two macromolecules share the similar inherent elasticity in DOSM due to their same chain backbone. However, obvious elastic deviations can be observed in aqueous conditions. Especially, a lower pH value (acid environment) is helpful to increase the elasticity of both chitin and chitosan. On the contrary, the tendency of elastic variation of chitin and chitosan in a larger pH value (alkaline environment) shows obvious diversity, which is mainly determined by the side groups. This basic study may produce enlightenment for the design of intelligent chitin and chitosan food packaging and biomedical materials.
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Affiliation(s)
- Song Zhang
- Department of Food Science and Engineering, Moutai Institute, Renhuai 564502, China; (Y.J.); (Y.H.); (J.D.); (H.L.)
| | | | | | | | | | - Shirui Yu
- Department of Food Science and Engineering, Moutai Institute, Renhuai 564502, China; (Y.J.); (Y.H.); (J.D.); (H.L.)
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Di L, Cheng S, Zhu Y, Jin Y, Qi C, Zhang L, Zhang M, Wang X, Han Y, Li XL, Min JZ. Development of a diphenyl sulfide structure derivatization reagent for amino acid enantiomers analysis: Application of dynamic monitoring in human urine after drinking wine. J Chromatogr A 2023; 1688:463698. [PMID: 36528900 DOI: 10.1016/j.chroma.2022.463698] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022]
Abstract
We developed a novel chiral mass spectrometry derivatization reagent (S)-(3-(4-carboxythiazolidin-3-yl)-3-oxopropyl) diphenylsulfonium (CTOD) with a positively charged sulfur-containing structure for high-sensitivity detection of the chiral resolution of amino acid enantiomers. CTOD reacted with DL-amino acids at 60oC for 60 min to generate the corresponding diastereomers, fifteen chiral amino acid-derived products were separated. Resolution (Rs) values were of the range 1.54-4.36, except Asn 1.07, achieving good separation. A highly sensitive and selective UHPLC-MS/MS method for the simultaneous determination and chiral separation of five chiral amino acids (Pro, Ala, Glu, Asp, and Phe) based on CTOD derivatization was established and applied to the detection of chiral amino acids in different wines. The diastereomeric resolution of the five amino acids was 1.71-5.42, and an excellent linear relationship was obtained in the range of 0.25-500 pmol (R2 ≥0.9993). The detection limit was 0.05-0.25 pmol. The intra- and inter-day precisions were 0.51-5.76% and 0.78-5.18%, respectively, and the average recovery was 90.03-99.99%. In addition, the metabolic concentration of chiral amino acids was monitored after drinking red wine and white wine, and the fitting curve of metabolic concentration was drawn.
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Affiliation(s)
- Lei Di
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Shengyu Cheng
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Yan Zhu
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Yueying Jin
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Chao Qi
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Lingli Zhang
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Minghui Zhang
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Xin Wang
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China
| | - Yu Han
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China.
| | - Xi-Ling Li
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China.
| | - Jun Zhe Min
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, Department of Pharmaceutical Analysis, College of Pharmacy Yanbian University, Yanji, Jilin 133002, China.
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Enhanced carboxypeptidase efficacies and differentiation of peptide epimers. Anal Biochem 2021; 642:114451. [PMID: 34774536 DOI: 10.1016/j.ab.2021.114451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/20/2021] [Accepted: 11/04/2021] [Indexed: 11/24/2022]
Abstract
Carboxypeptidases enzymatically cleaves the peptide bond of C-terminal amino acids within peptides. In humans, it is involved in enzymatic synthesis and maturation of proteins and peptides. Carboxypeptidases A and Y have difficulty hydrolyzing the peptide bond of dipeptides and some other amino acid sequences. Early investigations into different N-blocking groups concluded that larger moieties increased substrate susceptibility to peptide bond hydrolysis with carboxypeptidase. This study conclusively demonstrates that 6-aminoquinoline-N-hydroxysuccimidyl carbamate (AQC) as an N-blocking group greatly enhances substrate hydrolysis with carboxypeptidase. AQC addition to the N-terminus of amino acids and peptides also improves chromatographic peak shape and sensitivities via mass spectrometry detection. These enzymes have been used for amino acid sequence determination prior to the advent of modern proteomics. However, most modern proteomic methods assume that all peptides are comprised of l-amino acids and therefore cannot distinguish L-from d-amino acids within the peptide sequence. The majority of existing methods that allow for chiral differentiation either require synthetic standards or incur racemization in the process. This study highlights the resistance of d-amino acids within peptides to enzymatic hydrolysis by Carboxypeptidase Y. This stereoselectivity may be advantageous when screening low abundance peptide epimers.
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