1.Expression, purification and characterization of N-glycanase from Schizosaccharomyces pombe in Escherichia coli.
Fengxue XIN ; Peng WANG ; Shenghua ZHONG ; Qingsheng QI
Chinese Journal of Biotechnology 2008;24(4):592-597
One pair of primers were designed and synthesized on the base of the cDNA sequence encoding Schizosaccharomyces pombe N-glycanase reported on the GenBank. The cDNA sequence encoding Peptide N-glycanase was cloned from the Schizosaccharomyces pombe by RT-PCR. And then the RT-PCR product was cloned into the expression vector pET-15b. The expression vector pET-15b(+)/Png1p was transformed into E. coli BL21(DE3). The results showed that the relative molecular weight of the enzyme was determined to be approximately 39 kD using SDS-PAGE. The expression products after induction and purification can catalyze the cleavage of N-linked oligosaccharides from glycoprotein coped with heat, but have no action on the native glycoprotein with the help of DTT. The percentage of deglycosylated RNase B treated with equate Png1p in different reaction temperature, pH, concentration of DTT and denatured temperature showed that the optimum temperature, the optimum pH is 30 degrees C; the optimum concentration of DTT is 10 mmol/L and the optimum denatured temperature is 100 degrees C.
Cloning, Molecular
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Escherichia coli
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genetics
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metabolism
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Glycosylation
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Hydrogen-Ion Concentration
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Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
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biosynthesis
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genetics
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metabolism
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Recombinant Proteins
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biosynthesis
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genetics
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isolation & purification
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Schizosaccharomyces
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enzymology
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genetics
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Temperature
2.Role of spherical aberration and coma in orthokeratology for myopia control
Shoukuan ZHANG ; Qingsheng PENG ; Lei ZHANG
International Eye Science 2024;24(1):88-92
As a highly prevalent global condition, myopia significantly impacts the ocular health of young individuals in China. Orthokeratology lens, as a rigid corneal contact lens, has demonstrated effective control over the progression of myopia; however, its mechanism of action remains incompletely elucidated. As one of the factors influencing visual acuity, higher-order aberrations will undergo marked changes after orthokeratology, with particular emphasis on the alterations in spherical aberrations and coma. The changes in corneal morphology induced by orthokeratology lead to significant positive increase in both spherical aberration and coma. Furthermore, the elevation of spherical aberration and coma demonstrates a negative correlation with the rate of axial length growth following orthokeratology. The interplay among spherical aberration, coma, defocus, accommodation, astigmatism, and pseudo-accommodation may constitute the underlying mechanism governing the control of myopia through orthokeratology.