Stabilizers of horseradish peroxidase / 生物工程学报

Keeping an enzyme in its native form with high catalytic activity is of great significance. In the present study, thermal stabilizers of horseradish peroxidase (HRP) were screened. The results indicated that thermal stability of HRP was enhanced by magnesium sulphate and gelatin. A synergic effect of magnesium sulphate and gelatin was observed. In the presence of the stabilizer, the enzymatic activity of HRP remained 89% after kept for 80 h at 50 degrees C and 57% for 90 days at room temperature. Thermal alterations of HRP structure in the absence and presence of the stabilizers were explored by using UV absorption spectra at 402 nm (Soret band), intrinsic fluorescence and 8-anilinonaphthalene-1-sulfonic acid (ANS) fluorescence. The results suggested that magnesium sulphate and gelatin attenuated the extent of unfolding of HRP and therefore the native enzyme structure was stabilized.

Protective effect of dimethylsulfoxide on axon degeneration / 第二军医大学学报

Objective:To investigate the protective effect of dimethylsulfoxide(DMSO) on axon degeneration.(Methods: Cultured) rat superior cervical ganglia were treated with DMSO(100%,10 ?l) per well to disconnect axons from the cell bodies.SCGs in DMSO control group were treated with a mixture of DMSO(10 ?l) and medium (2 ml) per well;in positive control group were transfected with herpes simplex virus over-expressing Wld~S protein and the cell body was eliminated;and in blank control group were treated with 10 ?l PBS.The separated axons were fixed with 4% poly formaldehyde at 0,4,8,12 and 24 h after treatment with DMSO for immunostaining with specific antibody to microtubulin.Thus,the changes of axonal structure were investigated.The axonal protein was collected and the degeneration of neurofilament was detected by Western Blotting.Results: In DMSO disconnected group,the axonal morphology and structure showed no obvious change at 12 h post disconnection,but slight degeneration was observed at 24 h post disconnection.The degradation of microtubulin was obviously slowed down and their axonal structures maintained intact 12 h later.The neurofilament could be detected 12 h after disconnection.The above changes in disconnected group were similar to those in positive control group.No obvious protective effects on axonal degeneration were observed in blank and DMSO control groups.Conclusion: Local high concentration of DMSO can delay axonal degeneration,which indicates that DMSO can be used for adjuvant treatment of neurodegenerative diseases.

ULTRA VIOLET DIFFERENTIAL SPECTROMETRY FOR DIRECT DETERMINATION OF ASCORBIC ACID / 营养学报

This paper reports a method for direct determination of ascorbic acid by ultra-violet differential spectrometry and its application to analysis of ascorbic acid contents in vegetables, fruits and tablets. All the four (1st to 4th) derivatives of spectrometry were available for determination, and the better results were obtained from the 2nd derivative spectrometry. The results showed that this method was simple, rapid and accurate.