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Objective： Optimize the preparation process of salt-soluble porcine liver protein and improve the utilization rate of porcine liver by-products. Methods： Taking the extraction rate as the index, the effects of NaCl concentration, pH, extraction time and solid-liquid ratio on the extraction rate of SSLP were analyzed, and the optimal preparation process was determined by orthogonal rotation optimization test. Taking water soluble liver proteins （WSLP） as the control, the functional characteristics （solubility, foaming, foam stability, emulsification, emulsification stability, etc.） of SSLP were compared and analyzed, and Fourier transform infrared spectroscopy （FT-IR） was used, the structural changes were analyzed by low field nuclear magnetic resonance （LF-NMR） and differential scanning calorimetry （DSC）. Results： The optimum extraction process of SSLP was NaCl concentration 0.4 mol/L, pH 8, extraction time 12.95 h, solid-liquid ratio 1∶4.6 (g/mL), and the extraction rate was 10.60%. FT-IR analysis showed that the absorption peak of characteristic functional groups of SSLP was obvious and in the secondary structure β-The relative content of corner was 39.91%, α-The relative content of helix was 13.55%, β-The relative content of folding was 21.32%, and the relative content of random curl was 25.23%; LF-NMR analysis showed that SSLP had higher bound water and higher water retention; DSC results showed that the denaturation temperature of SSLP was 78.68 ℃. Conclusion： SSLP prepared under optimal process conditions has better solubility, foaming, emulsification and emulsification stability than WSLP, which is a high-quality source for the development of pig liver protein products.

Polypeptides, as natural polyelectrolytes, are assembled into tailored proteins to integrate chromophores and catalytic sites for photosynthesis. Mimicking nature to create the water‐soluble nanoassemblies from synthetic polyelectrolytes and photocatalytic molecular species for artificial photosynthesis is still rare. Here, we report the enhancement of the full‐spectrum solar‐light‐driven H2 production within a supramolecular system built by the co‐assembly of anionic metalloporphyrins with cationic polyelectrolytes in water. This supramolecular photocatalytic system achieves a H2 production rate of 793 and 685 μmol h−1 g−1 over 24 h with a combination of Mg or Zn porphyrin as photosensitizers and Cu porphyrin as a catalyst, which is more than 23 times higher than that of free molecular controls. With a photosensitizer to catalyst ratio of 10000 : 1, the highest H2 production rate of >51,700 μmol h−1 g−1 with a turnover number (TON) of >1,290 per molecular catalyst was achieved over 24 h irradiation. The hierarchical self‐assembly not only enhances photostability through forming ordered stackings of the metalloporphyrins but also facilitates both energy and electron transfer from antenna molecules to catalysts, and therefore promotes the photocatalysis. This study provides structural and mechanistic insights into the self‐assembly enhanced photostability and catalytic performance of supramolecular photocatalytic systems. [ABSTRACT FROM AUTHOR]

Rationale: Deuterium‐labeled organic compounds, reagents, and drugs are widely used in many scientific research fields. Isotopic purity as the feature parameter of deuterated compounds is of great importance. In this article, we used electrospray ionization with high‐resolution mass spectrometry (ESI‐HRMS) to study isotopic purity of deuterium‐labeled organic compounds based on assigning and distinguishing the corresponding H/D (hydrogen–deuterium) isotopolog ions of deuterated compounds. Methods: We systematically considered the specific requirements of accuracy and resolution of ESI‐HRMS when measuring isotopic purity and demonstrated some actual cases using ESI‐HRMS and ultraperformance liquid chromatography (UPLC)‐HRMS. Meanwhile, ESI‐HRMS/MS of deuterated compounds was performed to obtain more information on deuterium‐labeled position characterization. Results: Two isotopic purity calculation methods based on the relative abundance in ESI‐HRMS and UPLC‐HRMS of H/D isotopolog ions (D0–Dn) were compared, which gave consistent isotopic purity values and were in good agreement with the certified isotopic purity values. We further studied and monitored the H/D exchange reaction of ethyl 3‐(4‐bromophenyl)‐3‐oxopropanoate (EBPO) by evaluating the dynamic isotopic purity changes in EBPO‐D2 in the H/D exchange reaction in situ. Conclusion: The isotopic purity characterization methods using ESI‐HRMS discussed in this article have some outstanding advantages: rapid, highly sensitive, very low sample consumption (even below nanogram level), and deuterated solvent‐free. Thus, this low‐impact analytical method requires less time and is cost effective and might have good application potential for in‐situ isotopic purity analysis and for monitoring the H/D exchange reactions. [ABSTRACT FROM AUTHOR]