Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted t...Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted to dihydroxyacenaphthene after 48 h. By control of the reaction time and in the presence of DMF as co-solvent, the reduction of 6-substituted acenaphthenequinones under vigorous agitation afforded the corresponding 2-hydroxyacenaphthenones in 24-84% yields with 10-93% ee.展开更多
The baker's yeast Saccharomyces(S.)cerevisiae is a single-celled eukaryotic model organism widely used in research on life sciences.Being a unicellular organism,S.cerevisiae has some evident limitations in applica...The baker's yeast Saccharomyces(S.)cerevisiae is a single-celled eukaryotic model organism widely used in research on life sciences.Being a unicellular organism,S.cerevisiae has some evident limitations in application to neuroscience.However,yeast prions are extensively studied and they are known to share some hallmarks with mammalian prion protein or other amyloidogenic proteins found in the pathogenesis of Alzheimer's,Parkinson's,or Huntington's diseases.Therefore,the yeast S.cerevisiae has been widely used for basic research on aggregation properties of proteins in cellulo and on their propagation.Recently,a yeast-based study revealed that some regions of mammalian prion protein and amyloidβ1–42 are capable of induction and propagation of yeast prions.It is one of the examples showing that evolutionarily distant organisms share common mechanisms underlying the structural conversion of prion proteins making yeast cells a useful system for studying mammalian prion protein.S.cerevisiae has also been used to design novel screening systems for anti-prion compounds from chemical libraries.Yeastbased assays are cheap in maintenance and safe for the researcher,making them a very good choice to perform preliminary screening before further characterization in systems engaging mammalian cells infected with prions.In this review,not only classical red/white colony assay but also yeast-based screening assays developed during last year are discussed.Computational analysis and research carried out using yeast prions force us to expect that prions are widely present in nature.Indeed,the last few years brought us several examples indicating that the mammalian prion protein is no more peculiar protein–it seems that a better understanding of prion proteins nature-wide may aid us with the treatment of prion diseases and other amyloid-related medical conditions.展开更多
Leech hyaluronidase(LHyal)is a hyperactive hyaluronic acid(HA)hydrolase that belongs to the hyaluronoglu-curonidase family.Traditionally,LHyal is extracted from the heads of leeches,but the recent development of the P...Leech hyaluronidase(LHyal)is a hyperactive hyaluronic acid(HA)hydrolase that belongs to the hyaluronoglu-curonidase family.Traditionally,LHyal is extracted from the heads of leeches,but the recent development of the Pichia pastoris recombinant LHyal expression method permitted the industrial production of size-specific HA oligosaccharides.However,at present LHyal expressed by recombinant yeast strains requires laborious protein purification steps.Moreover,the enzyme is deactivated and removed after single use.To solve this problem,we developed a recyclable LHyal biocatalyst using a yeast surface display(YSD)system.After screening and charac-terization,we found that the cell wall protein Sed1p displayed stronger anchoring to the P.pastoris cell wall than other cell wall proteins.By optimizing the type and length of the linkers between LHyal and Sed1p,we increased the activity of enzymes displayed on the P.pastoris cell wall by 50.34%in flask cultures.LHyal-(GGGS)6-Sed1p activity further increased to 3.58×105 U mL−1 in fed-batch cultivation in a 5 L bioreactor.Enzymatic prop-erty analysis results revealed that the displayed LHyal-(GGGS)6-Sed1p generated the same oligosaccharides but exhibited higher thermal stability than free LHyal enzyme.Moreover,displayed LHyal-(GGGS)6-Sed1p could be recovered easily from HA hydrolysis solutions via low-speed centrifugation and could be reused at least 5 times.YSD of LHyal not only increased the utilization efficiency of the enzyme but also simplified the purification pro-cess for HA oligosaccharides.Thus,this study provides an alternative approach for the industrial preparation of LHyal and HA oligosaccharides.展开更多
Immobilization techniques and biocatalytic transformations performed in organic media are new developing methods for organic reactions. Baker's yeast was immobilized on the alginate supports. This preparation cont...Immobilization techniques and biocatalytic transformations performed in organic media are new developing methods for organic reactions. Baker's yeast was immobilized on the alginate supports. This preparation contained about 20% of dry yeast cells. The immobilized Baker's yeast were found to be very effective in the reduction of o-benzoquinone, p-benzoquinones, naphthoquinones, and anthraquinones in hexane.展开更多
A regio- and stereo-selective reduction of diketo-n-butylphosphonates by baker's yeast was reported. The chemical yield and ee value of these reactions are highly dependent on the structure of substrates. The re...A regio- and stereo-selective reduction of diketo-n-butylphosphonates by baker's yeast was reported. The chemical yield and ee value of these reactions are highly dependent on the structure of substrates. The resulting optical active hydroxy^alkanephosphonates can be used as chirons for the synthesis of polyfunctional organophosphorus compounds. As useful building block, a series of α,β-unsaturated ketones bearing chiral hydroxy group in addition to trifluoromethyl moiety was prepared via the Horner-Wadsworth-Emmons (HWE) reaction of the biotransformation products.展开更多
文摘Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted to dihydroxyacenaphthene after 48 h. By control of the reaction time and in the presence of DMF as co-solvent, the reduction of 6-substituted acenaphthenequinones under vigorous agitation afforded the corresponding 2-hydroxyacenaphthenones in 24-84% yields with 10-93% ee.
基金funded by the Polish National Science Centre MINIATURA3,grant No.501/66 GR-6220(to TI)。
文摘The baker's yeast Saccharomyces(S.)cerevisiae is a single-celled eukaryotic model organism widely used in research on life sciences.Being a unicellular organism,S.cerevisiae has some evident limitations in application to neuroscience.However,yeast prions are extensively studied and they are known to share some hallmarks with mammalian prion protein or other amyloidogenic proteins found in the pathogenesis of Alzheimer's,Parkinson's,or Huntington's diseases.Therefore,the yeast S.cerevisiae has been widely used for basic research on aggregation properties of proteins in cellulo and on their propagation.Recently,a yeast-based study revealed that some regions of mammalian prion protein and amyloidβ1–42 are capable of induction and propagation of yeast prions.It is one of the examples showing that evolutionarily distant organisms share common mechanisms underlying the structural conversion of prion proteins making yeast cells a useful system for studying mammalian prion protein.S.cerevisiae has also been used to design novel screening systems for anti-prion compounds from chemical libraries.Yeastbased assays are cheap in maintenance and safe for the researcher,making them a very good choice to perform preliminary screening before further characterization in systems engaging mammalian cells infected with prions.In this review,not only classical red/white colony assay but also yeast-based screening assays developed during last year are discussed.Computational analysis and research carried out using yeast prions force us to expect that prions are widely present in nature.Indeed,the last few years brought us several examples indicating that the mammalian prion protein is no more peculiar protein–it seems that a better understanding of prion proteins nature-wide may aid us with the treatment of prion diseases and other amyloid-related medical conditions.
基金supported by the National Natural Science Foundation of China(32000058)the Jiangsu Province Natural Science Fund for Distinguished Young Scholars(BK20200025)the National Key Research and Development Program of China(2021YFC2103100).
文摘Leech hyaluronidase(LHyal)is a hyperactive hyaluronic acid(HA)hydrolase that belongs to the hyaluronoglu-curonidase family.Traditionally,LHyal is extracted from the heads of leeches,but the recent development of the Pichia pastoris recombinant LHyal expression method permitted the industrial production of size-specific HA oligosaccharides.However,at present LHyal expressed by recombinant yeast strains requires laborious protein purification steps.Moreover,the enzyme is deactivated and removed after single use.To solve this problem,we developed a recyclable LHyal biocatalyst using a yeast surface display(YSD)system.After screening and charac-terization,we found that the cell wall protein Sed1p displayed stronger anchoring to the P.pastoris cell wall than other cell wall proteins.By optimizing the type and length of the linkers between LHyal and Sed1p,we increased the activity of enzymes displayed on the P.pastoris cell wall by 50.34%in flask cultures.LHyal-(GGGS)6-Sed1p activity further increased to 3.58×105 U mL−1 in fed-batch cultivation in a 5 L bioreactor.Enzymatic prop-erty analysis results revealed that the displayed LHyal-(GGGS)6-Sed1p generated the same oligosaccharides but exhibited higher thermal stability than free LHyal enzyme.Moreover,displayed LHyal-(GGGS)6-Sed1p could be recovered easily from HA hydrolysis solutions via low-speed centrifugation and could be reused at least 5 times.YSD of LHyal not only increased the utilization efficiency of the enzyme but also simplified the purification pro-cess for HA oligosaccharides.Thus,this study provides an alternative approach for the industrial preparation of LHyal and HA oligosaccharides.
基金Project supported by the National Natural Science Foundation of China and the Guangdong Science Foundation of Guangdong Province.
文摘Immobilization techniques and biocatalytic transformations performed in organic media are new developing methods for organic reactions. Baker's yeast was immobilized on the alginate supports. This preparation contained about 20% of dry yeast cells. The immobilized Baker's yeast were found to be very effective in the reduction of o-benzoquinone, p-benzoquinones, naphthoquinones, and anthraquinones in hexane.
文摘A regio- and stereo-selective reduction of diketo-n-butylphosphonates by baker's yeast was reported. The chemical yield and ee value of these reactions are highly dependent on the structure of substrates. The resulting optical active hydroxy^alkanephosphonates can be used as chirons for the synthesis of polyfunctional organophosphorus compounds. As useful building block, a series of α,β-unsaturated ketones bearing chiral hydroxy group in addition to trifluoromethyl moiety was prepared via the Horner-Wadsworth-Emmons (HWE) reaction of the biotransformation products.
