Detail of "5978-70-1"

Reference

Aliphatic optically active alcohols by enzyme-aided syntheses

Aliphatic optically active alcohols by enzyme-aided syntheses.Some chemicals with cas registry numbers like 5978-70-1 and 20281-86-1 are also used. Jeromin, Gunter E.; Scheidt, Annette (Abt. Juelich, Fachhochsch. Aachen, Juelich D-5170, Germany). Tetrahedron Lett., 32(48), 7021-4 (English) 1991. CODEN: TELEAY. ISSN: 0040-4039. DOCUMENT TYPE: Journal CA Section: 23 (Aliphatic Compounds) Section cross-reference(s): 9, 26 Some optically active aliph. alcs., including matsutake alc., were easily obtained by irreversible enantioselective transesterification with vinyl laurate in presence of Pseudomonas lipase. .

Substrate specificity and stereoselectivity of horse liver alcohol dehydrogenase

Substrate specificity and stereoselectivity of horse liver alcohol dehydrogenase. Kinetic evaluation of binding and activation parameters controlling the catalytic cycles of unbranched, acyclic secondary alcohols and ketones as substrates of the native and active-site-specific cobalt(II)-substituted enzyme. Adolph, Hans W.; Maurer, Patrik; Schneider-Bernloehr, Helga; Sartorius, Christian; Zeppezauer, Michael (Univ. Saarlandes, Saarbruecken W-6600, Germany). Eur. J. Biochem., 201(3), 615-25 (English) 1991. 5978-70-1 and 31087-44-2 are also occured in this study. CODEN: EJBCAI. ISSN: 0014-2956. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) The steady-state kinetic parameters, kcat and Km, and the rate consts. of hydride transfer for the substrates: isopropanol/acetone; (S)-2-butanol,(R)-2-butanol/2-butanone; (S)-2-pentanol,(R)-2-pentanol/2-pentanone; 3-pentanol/3-pentanone; (S)-2-octanol and (R)-2-octanol were detd. for the native Zn(II)-substituted horse liver alc. dehydrogenase (LADH) and the specific active-site-substituted Co(II)-LADH. A combined evaluation of enzyme (E) steady-state kinetic data and rate consts. obtained from stopped-flow measurements, allowed the detn. of all rate consts. of the following ordered bi-bi mechanism: E t E×NAD t E×NAD.R1R2CHOH t E×NADH×R1R2CO t E×NADH t E. On the basis of the different substrate specificities of LADH and yeast alc. dehydrogenase (YADH), a procedure was developed to evaluate the enantiomeric product compn. of the ketone redns. The redn. of 2-butanone and 2-pentanone revealed (S)-2-butanol (86%) and (S)-2-pentanol (95%) as the major products. The obsd. enantioselectivity implied the existence of 2 productive ternary complexes: E×NADH×(pro-S)-2-butanone and E×NADH×(pro-R)-2-butanone. All rate consts. describing the kinetic pathways of the system: (S)-2-butanol,(R)-2-butanol/2-butanone were detd. These data were used to est. the expected enantiomer product compn. of 2-butanone redns. using apparent kcat/Km values for the 2 different ternary-complex configurations of 2-butanone. Addnl., these data were used for computer simulations of the corresponding reaction cycles. The calcd., simulated, and exptl. data were found to be in good agreement. Thus, the system: (S)-2-butanol,(R)-2-butanol/2-butanone is the 1st example of a LADH-catalyzed reaction for which the stereochem. course could be described in terms of rate consts. of the underlying mechanism. The effects of Co(II) substitution on the different steps of the kinetic pathway were also investigated. The free energy of activation was higher for alc. oxidn. than ketone redn. with Co(II)-LADH in comparison to Zn(II)-LADH. However, the free energies of binding were affected by metal substitution in such a way that the enantioselectivity of ketone redn. was not significantly changed by the substitution of Co(II) for Zn(II). Evaluation of the data showed that substrate specificity and stereoselectivity resulted from combination of the free energies of binding and activation, with differences in binding energies as the dominating factors. In this regard, the interactions of substrate mols. with the protein moiety were dominant over the interactions with the catalytic metal ion. .