Die Umsetzung von trans-2@-Benzamino-cholestanol-(3oc) und trans-3cr-Benza m i n o -c~o i~t a n o~-( 2~~ rnit Thionylchlorid fiihrt zu Oxazolinen, die auch aus den Sulfonsaureestern dieser Acylamine mit Alkali gewonnen werden konnen. Durch kurzes Erhitzen mit Salzsaure entstehen aus den Oxazolinen cis-Aminoalkoholester-hydrochloride und bei energischer Verseifung die freien Aminoalkohole. Die cis-Aminoalkohole geben O+N-und N-tO-Acylwanderung.
PONSOLD und HAFNERJahrg. 98
The effect of a n enzyme preparation of Strqtomyces spec. KT3 was tested in view of its cell wall 1 ytic activity on cells of Saccharomyces cerevisiue. According to electron micrographs under the influence of the enzyme preparation protoplasts but no spheroplasts were formed. The yield of protoplasts amounted dependent on the enzyme charge to 75-99 per cent, most of the protoplasts were released after 60 minutes. Cells of 12 strains of Saccharomyces cerevisiae were able to be protoplasted and stabilized immediately thereafter by mannitol (0.8 M) or KCI (0.6 M). The presence of stabilizers already in the enzyme-containing medium inhibited, however, protoplasting considerably. The stabilized protoplasts could be stored for six days a t 4OC without any noticeable changes.
EinfiihrungBiotechnologische Verfahren mit Mikroorganismen setzen leistungsstarke Stamme vokaus. Es ist deshalb eine vorrangige Aufgabe, die Leistungciparameter bestimmter Stamme zu verbecisern oder neue ProduktionsstBmme zu schaffen, die hohe Biomasse-bzw. Produktausbeuten gewahrleisten. Um dieses Ziel zu erreichen, bedient man sich verschiedener Methoden, eine davon ist die in den letzten Jahren mehrfach angewandte Methode der Genomzusammenfuhrung auf parasexuellem Wege durch induzierte Fusion von Protoplasten selektierter Stamme (u-a. FERENCZY [l], ALFOLDI [2], MACH [3]). Sehr haufig wurden zur Protoplastierung der Magendarmsaft von Helix pamatia oder daraus hergestellte Enzyme eingesetzt (EDDY u. WILLIAMSON [4], PEBERDY [5], DIA-TEWA et al. [6], WEBER [7] u. a.). Eine weitere Moglichkeit, Protoplasten zu gewinnen, ergibt sich durch Anwendung zellwandlytischer mikrobieller Enzyme (9. Kuo u. Y m -MOTO [8] sowie POPOV u. KONSTANTINOVA [9]). Wir untersuchten die Wirkung eines Streptomyceten-Enzympraparates auf die Protoplastenbildung verschiedener Stamme von Saecharomyces ceremkiae.
Subtilisin DY as well as alkaline protease from Bacillus licheniformis 41 p catalyze the hydrolysis of (1SR, 5RS, 6RS, 7RS)‐7‐acetoxy‐6‐acetoxymethyl‐2‐oxabicyclo[3.3.0]octan‐3‐one (rac‐1) with practically useful enantio‐ and regioselectivity. Under the hitherto found optimal conditions (1S, 5R, 6R, 7R)‐7‐hydroxy‐6‐hydroxymethyl‐2‐oxabicyclo[3.3.0]octan‐3‐one (4), an important intermediate in prostaglandin syntheses, could be prepared in a yield of 16% with an enantiomeric excess of 99%. The enantiomer (ent‐4) was obtained with the same enantiomeric excess in 20% yield. The chemical yields are related to the racemic starting material rac‐1.
(1S,4R)-4-Hydroxycyclopent-2-enyl-acetate (1), an attractive starting material for the synthesis of prostaglandins, was readily prepared by an enzyme-catalyzed interesterification procedure using acetic anhydride as acylation agent. As the chemical yield of the chiral monoacylation product is rather low (45%), we investigated the acylation mechanism of this reaction to optimize the product output. Kinetic measurements were carried out by means of gas chromatography on a chiral stationary phase, synthesized by methylation of β-cyclodextrin.
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