Spektralphotometrische Bestimmung des Molekulargewichts von Dextran

Ohne Zusammenfassung

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Spectrophotometric determination of the molecular weight of Dextran

     

Kinetics of asparaginase II fermentation in Saccharomyces cerevisiae ure2dal80 mutant

Although the quality of nitrogen source affects fermentation product formation, it has been managed empirically, to a large extent, in industrial scale. Laboratory-scale experiments successfully use the high-cost proline as a nonrepressive source. We evaluated urea as a substitute for proline in Saccharomyces cerevisiae ure2dal80 fermentations for asparaginase II production as a model system for nitrogen-regulated external enzymes. Maximum asparaginase II levels of 265 IU/L were observed in early stationary-phase cells grown on either proline or urea, whereas in ammonium cells, the maximum enzyme level was 157 IU/L. In all cases, enzyme stability was higher in buffered cultures with an initial pH of 6.5.     

Spectrophotometric determination of some steroid sex-hormones

Summary A detailed spectrophotometric study of the reaction of estrogens and androgens with 98% sulphuric acid at 20° C and of the effect of various dilutions with water on the nature of the spectra is presented. Dilution of the androgens-acid and estrogens-acid solutions with water to 40% and 80% v/v acid, respectively, increases the absorption intensity 3 to 11 times. The optimum conditions for determination of down to 2g/ml of estrone, estradiol, ethinylestradiol, testosterone, and rostanalone and progesterone are reported. The results show a relative standard deviation of +-1.5 %.

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Spektralphotometrische Bestimmung einiger Steroid-Sexualhormone

Zusammenfassung Die Reaktion der Östrogene und Androgene mit 98%iger Schwefelsäure bei 20° C und der Einfluß von Verdünnungen. mit Wasser auf die Art der Spektren wurden eingehend untersucht. Verdünnungen auf einen Säuregehalt von 40% und 80% bewirken eine 3–11fache Zunahme der Absorption. Die optimalen Bedingungen zur Bestimmung von >2g/ml Östron, Östradiol, Äthinylöstradiol, Testosteron, Androstanalon und Progesteron wurden ausgearbeitet. Die relative Standardabweichung beträgt+-1,5%.