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Tn antigen (CD175), recognized as the precursor monosaccharide (α-GalNAc) of mucin O-glycan, is a well-known tumor-associated carbohydrate antigen (TACA). It has emerged as a potential biomarker for cancer diagnosis and prognosis. However, the role it plays in cancer biology remains elusive due to the absence of a sensitive and selective detection method. In this study, we synthesized two new probes based on a unique uridine-5'-diphospho-α-d-galactose (UDP-Gal) derivative, each functionalized with either a fluorescence or a cleavable biotin tag, to develop an innovative one-step enzymatic labeling strategy, enabling the visualization, enrichment, and site-specific mapping of the Tn antigen with unparalleled sensitivity and specificity. Our versatile strategy has been successfully applied to detect and image Tn antigen across various samples, including the complex cell lysates, live cells, serum, and tissue samples. Compared to the traditional lectin method, this one-step enzymatic method is simpler and more efficient (>10/100-fold in sensitivity). Furthermore, it allowed us to map 454 Tn-glycoproteins and 624 Tn-glycosylation sites from HEK293F Tn+ and Jurkat cells. Therefore, our strategy provides an exceptionally promising tool for revealing the biological functions of the Tn antigen and advancing cancer diagnostics.

A novel β-primeverosidase-like enzyme, originating from the hypocotyl of soybeans, was isolated and characterized. This enzyme, with an estimated molecular weight of 44 kDa, was identified as a monomer and exhibited peak activity at 55 °C and pH 5.5. It demonstrated a specific and efficient hydrolysis of 1-octen-3-yl β-primeveroside (1-octen-3-yl prim) and 3-octanyl β-primeveroside (3-octanyl prim) but did not act on glucopyranosides. Mn 2+ significantly enhanced its activity, while Zn 2+ , Cu 2+ , and Hg 2+ exerted inhibitory effects. Kinetic analysis revealed a higher hydrolytic capacity toward 1-octen-3-yl prim. Partial amino acid sequences were determined and the N-terminal amino acid sequence was determined to be AIVAYAL ALSKRAIAAQ. The binding energy and binding free energy between the β-primeverosidase enzyme and its substrates were observed to be higher than that of β-glucosidase, thus validating its superior hydrolysis efficiency. Hydrogen bonds and hydrophobic interactions were the main types of interactions between β-primeverosidase enzyme and 1-octen-3-yl prim and 3-octanyl prim, involving amino acid residues such as GLU-470, TRP-463, GLU-416, TRP-471, GLN-53, and GLN-477 (hydrogen bonds) and PHE-389, TYR-345, LEU-216, and TYR-275 (hydrophobic interactions). This study contributes to the application of a β-primeverosidase-like enzyme in improving the release efficiency of glycosidically conjugated flavor substances.

Hexanal and ( E )-2-hexenal in soymilk mainly form during the soaking and grinding of soybeans. In this study, freshly dehulled soybeans were soaked or ground in the presence or absence of different enzyme inhibitors. The results showed that (1) 1-palmitoyl-2-linoleoyl- sn -3-phosphatidylcholine, 1-stearoyl-2-linoleoyl- sn -3-phosphatidylcholine, 1-palmitoyl-2-linolenoyl- sn -3-phosphatidylcholine, and 1-stearoyl-2-linolenoyl- sn -3-phosphatidylcholine were preferentially acted upon by lipoxygenases (LOXs) and made predominant contributions to hexanal/( E )-2-hexenal formation. Phospholipase A 2 (PLA 2 ) is one of the key enzymes for hexanal/( E )-2-hexenal formation. (2) The ratio of net increase in hexanal/( E )-2-hexenal and net decrease in linoleic acid/linolenic acid was close to 100% during soaking, but it was only 60% during grinding. Only 13-hydroperoxy octadecad(tr)ienoic acid (13-HPOD/T) was formed for the membrane LOX, but both 13- and 9-hydroperoxy octadecad(tr)ienoic acid (9-HPOD/T) were produced for the cytoplasm LOX. Thus, only the membrane LOX was involved during soaking, while both membrane- and cytoplasm-bound LOXs worked during grinding. (3) Hydroperoxides and hexanal/( E )-2-hexenal during soybean grinding were studied. PC hydroperoxides formed almost instantly and reached a maximum in 10 s, while fatty acid hydroperoxides and hexanal/( E )-2-hexenal formed relatively slowly and reached a maximum in 50 s. The experimental data were fitted to the integrated form of the Michaelis-Menten equation, and K m , V max , and k cat for the LOX, PLA 2 , and hydroperoxide lyase were obtained, respectively.

Kaixin Powder (KXP) is a classic formula for treating morbid forgetfulness in ancient China. To guarantee the efficacy and safety of KXP, a simple and accurate HPLC-DAD method has been established and validated for the quantitative analysis of seven bioactive compounds in KXP. Dehydrotumulosic acid (DTU) and dehydrotrametenolic acid (DTR) were quantified in KXP for the first time. Good chromatographic separation was conducted on a Kromasil 100-5 C 18 column (250 mm × 4.6 mm, 5 μm) by gradient elution using mobile phases containing acetonitrile and 0.1% formic acid aqueous solution at different detection wavelengths. The calibration curves of each compound showed good linearity ( r ≥ 0.9990), and the LOD and LOQ were in the ranges of 0.01-0.10 and 0.03-0.40 μg/mL, respectively. The relative standard deviations (RSDs) of intra-day and inter-day precisions were in the ranges of 0.45-1.74% and 0.56-2.32%, respectively. All recoveries were in the range of 93.6-105.5% with an RSD no more than 2.77%. These quantification results of seven compounds determined in the samples were further confirmed by HPLC-QTOF-MS/MS. This study provides a useful and simple method for analyzing the major bioactive compounds and improves the quality assessment research of KXP., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

A reliable analytical method for the simultaneous determination of famoxadone and oxathiapiprolin dissipation kinetics as well as the metabolites of oxathiapiprolin (IN-E8S72 and IN-WR791) in tomato and soil was developed. We studied the dissipation of famoxadone and oxathiapiprolin in tomatoes grown using different kinetic curves in the area of Beijing in 2015 and 2016. Our results show that the most suitable model for two fungicides in 2015 and 2016 was first-order kinetic and second-order kinetic with the half-lives of 3.4 to 5.2 and 2.4 to 3.0 days, respectively. In addition, we applied the dynamic plant uptake model dynamiCROP and combined it with results from the field experiments to investigate the uptake and translocation of famoxadone and oxathiapiprolin in the soil-tomato environment. Modeled and measured results of two years fitted well with R 2 values ranging from 0.8072 to 0.9221. The fractions of famoxadone and oxathiapiprolin applied during tomato cultivation that are eventually ingested by humans via residues in crop harvest were finally evaluated and found to be in the range of one part per thousand, that is one gram intake per kilogram applied.