The development of novel nanoparticles as a new generation therapeutic drug platform is an active field of chemistry and cancer research. In recent years, fullerene nanoparticles have received ...extensive attention due to their unique physical and chemical properties. Properly modified fullerene nanoparticles have excellent biocompatibility and significant anti-tumor activity, which makes them have broad application prospects in the field of cancer therapy. Therefore, understanding the anti-tumor mechanism of fullerene nanoparticles is of great significance for the design and development of anti-tumor drugs with low toxicity and high targeting. This review has focused on various anti-tumor mechanisms of fullerene derivatives and discusses their toxicity and their distribution in organisms. Finally, the review points out some urgent problems that need solution before fullerene derivatives as a new generation of anti-tumor nano-drug platform enter clinical research.
The members of the Old Yellow Enzyme (OYE) family are capable of catalyzing the asymmetric reduction of (
/
)-citral to (
)-citronellal-a key intermediate in the synthesis of L-menthol. The ...applications of OYE-mediated biotransformation are usually hampered by its insufficient enantioselectivity and low activity. Here, the (
)-enantioselectivity of Old Yellow Enzyme from
CICC1060 (OYE2y) was enhanced through protein engineering. The single mutations of OYE2y revealed that the sites R330 and P76 could act as the enantioselectivity switch of OYE2y. Site-saturation mutagenesis was conducted to generate all possible replacements for the sites R330 and P76, yielding 17 and five variants with improved (
)-enantioselectivity in the (
/
)-citral reduction, respectively. Among them, the variants R330H and P76C partly reversed the neral derived enantioselectivity from 32.66%
(
) to 71.92%
(
) and 37.50%
(
), respectively. The docking analysis of OYE2y and its variants revealed that the substitutions R330H and P76C enabled neral to bind with a flipped orientation in the active site and thus reverse the enantioselectivity. Remarkably, the double substitutions of R330H/P76M, P76G/R330H, or P76S/R330H further improved (
)-enantioselectivity to >99%
in the reduction of (
)-citral or (
/
)-citral. The results demonstrated that it was feasible to alter the enantioselectivity of OYEs through engineering key residue distant from active sites, e.g., R330 in OYE2y.
The gene encoding a (2R,3R)-2,3-butanediol dehydrogenase from Rhodococcus erythropolis WZ010 (ReBDH) was over-expressed in Escherichia coli and the resulting recombinant ReBDH was successfully ...purified by Ni-affinity chromatography. The purified ReBDH in the native form was found to exist as a monomer with a calculated subunit size of 37180, belonging to the family of the zinc-containing alcohol dehydrogenases. The enzyme was NAD(H)-specific and its optimal activity for acetoin reduction was observed at pH 6.5 and 55 °C. The optimal pH and temperature for 2,3-butanediol oxidation were pH 10 and 45 °C, respectively. The enzyme activity was inhibited by ethylenediaminetetraacetic acid (EDTA) or metal ions Al3+, Zn2+, Fe2+, Cu2+ and Ag+, while the addition of 10% (v/v) dimethyl sulfoxide (DMSO) in the reaction mixture increased the activity by 161.2%. Kinetic parameters of the enzyme showed lower Km values and higher catalytic efficiency for diacetyl and NADH in comparison to those for (2R,3R)-2,3-butanediol and NAD+. The activity of acetoin reduction was 7.7 times higher than that of (2R,3R)-2,3-butanediol oxidation when ReBDH was assayed at pH 7.0, suggesting that ReBDH-catalyzed reaction in vivo might favor (2R,3R)-2,3-butanediol formation rather than (2R,3R)-2,3-butanediol oxidation. The enzyme displayed absolute stereospecificity in the reduction of diacetyl to (2R,3R)-2,3-butanediol via (R)-acetoin, demonstrating its potential application on the synthesis of (R)-chiral alcohols.
The recombinant carbonyl reductase from
WZ010 (ReCR) demonstrated strict (
)-stereoselectivity and catalyzed the irreversible reduction of
-Boc-3-piperidone (NBPO) to (
)-
-Boc-3-hydroxypiperidine (
...)-NBHP, a key chiral intermediate in the synthesis of ibrutinib. The NAD(H)-specific enzyme was active within broad ranges of pH and temperature and had remarkable activity in the presence of higher concentration of organic solvents. The amino acid residue at position 54 was critical for the activity and the substitution of Tyr54 to Phe significantly enhanced the catalytic efficiency of ReCR. The
/
values of ReCR Y54F for NBPO, (
/
)-2-octanol, and 2-propanol were 49.17 s
mM
, 56.56 s
mM
, and 20.69 s
mM
, respectively. In addition, the (
)-NBHP yield was as high as 95.92% when whole cells of
overexpressing ReCR variant Y54F catalyzed the asymmetric reduction of 1.5 M NBPO for 12 h in the aqueous/(
/
)-2-octanol biphasic system, demonstrating the great potential of ReCR variant Y54F for practical applications.
Tea saponins have high surface-active and biological activities and are widely used in chemicals, food, pharmaceuticals, and pesticides. Tea saponins are usually extracted using ethanol or water, but ...both methods have their disadvantages, including a negative impact on the environment, high energy consumption, and low purity. In this study, we explored an effective process for extracting tea saponins from tea meal using deep eutectic solvents combined with ultrasonic extraction and enzymatic techniques. The experimental results showed that a high extraction efficiency of 20.93 ± 0.48% could be achieved in 20 min using an ultrasonic power of 40% and a binary DES consisting of betaine and ethylene glycol (with a molar ratio of 1:3) at a material–liquid ratio of 1:35 and that the purity of the tea saponins after purification by a large-pore adsorption resin reached 95.94%, which was higher than that of commercially available standard tea saponin samples. In addition, the extracted tea saponins were evaluated for their antioxidant and bacteriostatic activities using chemical and biological methods; the results showed that the tea saponins extracted using these methods possessed antioxidant properties and displayed significant antibacterial activity. Therefore, the present study developed a method for using deep eutectic solvents as an environmentally friendly technological solution for obtaining high-purity tea saponins from tea meal oil. This is expected to replace the current organic solvent and water extraction process and has great potential for industrial development and a number of possible applications.
The use of nanomedicines for cancer treatment has been widespread. Fullerenes have significant effects in the treatment of solid tumors. Here, we are going to study the effects of hydroxylated ...fullerene C
(OH)
(n = 18-22) treatment on chronic myeloid leukemia cell proliferation and investigate its toxicity. The results showed that hydroxylated fullerene C
(OH)
(n = 18-22) at low concentrations (less than 120 μM) not only had apparent toxic side effects, but also promoted the growth of K562 cells, while a high concentration of C
(OH)
had different degrees of inhibition on K562 cells. When the concentration is higher than 160 μM, the K562 cells showed morphological changes, the mitochondrial membrane potential decreased, the cell cycle was blocked in the stage of G2-phase, and cell apoptosis occurred, which may cause apoptosis, autophagy, and a variety of other damage leading to cell death. Meanwhile, it also indicated that its inhibition of solid tumors might be related to the tumor microenvironment; we verified the safety of fullerene without apparent cellular toxicity at a specific concentration.
Deep eutectic solvents (DESs) have physicochemical characteristics similar to those of ionic liquids but are more cost-effective, easier to produce, and less harmful to the environment, making them ...viable alternatives to ionic liquids. In this study, various DESs have been created to assess their potential as storage media for enzymes. The impact of the DES composition and water content on the thermal and storage stability of cellulase and pectinase was also investigated. Molecular simulation was used to examine the kinetic parameters of cellulase and pectinase in DESs with varying water levels based on choline chloride. The results demonstrated that the stability of the enzymes initially increased and then decreased with an increase in water content in DESs. The enzymes experienced secondary structural changes, leading to variations in fluorescence values. Ultimately, DESs can be utilized as a stabilizers for long-term enzyme preservation, and this study provides a theoretical basis for the coapplication of DESs and enzymes.
Pinelliapedatisecta agglutinin (PPA) has previously been used in labeling fractions of myeloid leukemia cells in our laboratory. We report here that a bacterial expressed recombinant PPA domain b ...tagged with soluble coxsackie and adenovirus receptor (sCAR-PPAb) preferentially recognized drug resistant cancer cells K562/ADR and H460/5Fu, as compared to their parental cell lines. Pretreatment of K562/ADR cells with sCAR-PPAb significantly enhanced phagocytosis of K562/ADR by macrophages in vivo. Meanwhile, in a K562/ADR xenograft model, intratumoral injection of sCAR-PPAb induced macrophage infiltration and phagocytosis. Furthermore, immunoprecipitation, mass spectrometry and Western blot identified the membrane target of PPA on K562/ADR as sarcolemmal membrane associated protein (SLMAP). An antibody against SLMAP significantly promoted the phagocytosis of K562/ADR by macrophages in vitro. These findings suggest that PPA not only could be developed into a novel agent that can detect drug resistant cancer cells and predict chemotherapy outcome, but also it has potential value in immunotherapy against drug resistant cancer cells through inducing the tumoricidal activity of macrophages.
This paper is concerned with optimization of fermentation conditions for lipstatin production with Streptomyces toxytricini zjut011 by the single factor and orthogonal tests. Five single factors of ...important effects on lipstatin production were explored. L-Leucine was identified to be the most suitable precursor for lipstatin biosynthesis and for the first time the divalent cations Mg2+, Co2+ and Zn2+ were found to have significant effect on enhancing lipstatin fermentation titer. The effects of the additives on the lipstatin production were in the order of L-leucine ＞ Mg2+ ＞ Co2+ ＞ Zn2+ ＞ octanoic acid. The optimized conditions for lipstatin production were determined as 45.72 mmol/L of L-leucine (added on the 4 th day), 31.1985 mmol/L of octanoic acid (added on the 6th day), 12 mmol/L of Mg2+, 1 mmol/L of Co2+ and 0.25 mmol/L of Zn2+. Under these conditions, a maximum lipstatin of 4.208 g/ml was achieved in verification experiments in 500 ml shake flasks.
A simple and reliable procedure was developed to screen biocatalysts with high alcohol dehydrogenase activity, efficient internal coenzyme regeneration, and high stereoselectivity. The strategy of ...activity screening in a microtitre plate format was based on the detection of fluorescence of NAD(P)H originating from the oxidation of alcohols. The primary and secondary screenings from soil samples yielded a versatile bacterial biocatalyst
Rhodococcus erythropolis
WZ010 demonstrating potential for the preparation of chiral aryl secondary alcohols. In terms of activity and stereoselectivity, the optimized reaction conditions in the stereoselective oxidation were 30 °C, pH 10.5, and 250 rpm, whereas bioreduction using glucose as co-substrate was the most favorable at 35 °C and pH 7.5 in the static reaction mixture. Under the optimized conditions, fresh cells of the strain stereoselectively oxidized the (
S
)-enantiomer of racemic 1-phenylethanol (120 mM) to acetophenone and afforded the unoxidized (
R
)-1-phenylethanol in 49.4 % yield and >99.9 % enantiomeric excess (
e.e.
). In the reduction of 10 mM acetophenone, the addition of 100 mM glucose significantly increased the conversion rate from 3.1 to 97.4 %. In the presence of 800 mM glucose, acetophenone and other aromatic ketones (80 mM) were enantioselectively reduced to corresponding (
S
)-alcohols with excellent
e.e.
values. Both stereoselective oxidation and asymmetric reduction required no external cofactor regeneration system.
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