The stereoselective hydrolysis of esmolol in whole blood and in its separated components from rat,rabbit and human was investigated.Blood esterase activities were variable in different species in the order of rat ＞ rabbit ＞ human.Rat plasma showed the high esterase activity and had no stereoselectivity to enantiomers.Rabbit red blood cell (RBC) membrane,RBC cytosol and plasma all hydrolyzed esmolol but with different esterase activity,whereas the hydrolysis in RBC membrane and cytosol showed significant stereoselectivity towards R-(+)-esmolol.Esterase in RBC cytosol from human blood mainly contributed to the esmolol hydrolysis,which was demonstrated with no stereoselctivity.Esterase in human plasma showed a low activity,but a remarkable stereoselectivity with R-(+)-esmolol.In addition,the protein concentration affected the hydrolysis behavior of esmolol in RBC suspension.Protein binding of esmolol enantiomers in human plasma,human serum albumin (HSA) and α1-acid glycoprotein (AGP) revealed that there was a significant difference in bound fractions between two enantiomers,especially for AGP.Our results indicated that the stereoselective protein binding might play a role in the different hydrolysis rates of esmolol enantiomers in human plasma.

AIM To study in vitro stereoselective metabolism of mandelic acid (MA) in 3 kinds of laboratory animal tissue fractions and observe the differences of MA biotransformation. METHODS MA enantiomers were incubated with the tissue fractions from rats, mice and rabbits. The phenylglyoxylic acid (PGA) concentrations in incubation mixture were determined by high-performance liquid chromatography. Coenzymes and inhibitors were co-incubated with MA to investigate their effects on MA metabolism. RESULTS Only S-MA showed a unique metabolism in liver and kidneys S9 fractions of rats. No inhibition of the enzyme activity was observed by addition of ethanol or 4-methyl pyrazole. NADPH caused a remarkable increase in S-MA metabolism. CONCLUSION Nonmicrosomal enzymes in kidneys and liver except alcohol dehydrogenase are responsible for the stereoselective metabolism of MA in rats. The MA biotransformation is significantly different between rats and mice or rabbits.

Response surface methodology was applied to optimize the fermentation conditions of FGFC1 (Fungi fibrinolytic compound 1). On the basis of single factor tests, response surface analysis was designed by Design-Expert, and the effects of culture time, ornithine hydrochloride addition and culture temperature on the yield of FGFC1 were studied, the predicted value and measured value were also contrasted. The results show the optimal culture conditions as follows: the culture time is 7 d, ornithine hydrochloride addition is 0.5% (M/V), culture temperature is 28 degrees C. Under these conditions, the yield of FGFC1 is 1 978.33 mg/L, which is consistent with the predicted value. It shows that the experiment is effective.
Culture Techniques ; methods ; Fermentation ; Fibrinolytic Agents ; metabolism ; Seawater ; microbiology ; Stachybotrys ; growth & development ; metabolism ; Surface Properties