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Frank Schulz

Publications and source records attributed to Frank Schulz.

4 recordsLinked to original sources
PubMed2006

Microbial Baeyer-Villiger oxidation: stereopreference and substrate acceptance of cyclohexanone monooxygenase mutants prepared by directed evolution.

[reaction: see text] An array of random mutants of cyclohexanone monooxygenase (CHMO) from Acinetobacter sp. NCIMB 9871 was screened against a library of structurally diverse ketones for modifications in the substrate acceptance profile and stereopreference of the enzymatic Baeyer-Villiger biooxidation. While the set of mutant biocatalysts was initially evolved for the enantiocomplementary oxidation of 4-hydroxycyclohexanone, improved and/or divergent stereoselectivities were observed for several substrates. In addition, expanded substrate acceptance to facilitate biotransformation of sterically demanding ketones was found.

Acinetobacter↗
PubMed2005

Towards practical biocatalytic Baeyer-Villiger reactions: applying a thermostable enzyme in the gram-scale synthesis of optically-active lactones in a two-liquid-phase system.

Baeyer-Villiger monooxygenases (BVMOs) are extremely promising catalysts useful for enantioselective oxidation reactions of ketones, but organic chemists have not used them widely due to several reasons. These include instability of the enzymes in the case of in vitro and even in vivo systems, reactant/product inhibition, problems with upscaling and the necessity of using specialized equipment. The present study shows that the thermally stable phenylacetone monooxygenase (PAMO) and recently engineered mutants can be used as a practical catalysts for enantioselective Baeyer-Villiger oxidations of several ketones on a preparative scale under in vitro conditions. For this purpose several parameters such as buffer composition, the nature of the solvent system and the co-factor regeneration system were optimized. Overall a fairly versatile and efficient catalytic system for enantioselective laboratory scale BV-oxidations of ketones was developed, which can easily be applied even by those organic chemists who are not well versed in the use of enzymes.

Journal Article↗
PubMed2004

Long-term efficacy and safety of mycophenolate mofetil in liver transplant recipients with calcineurin inhibitor-induced renal dysfunction.

Long-term survival after orthotopic liver transplantation (OLT) is mainly influenced by adverse events caused by immunosuppression. Several studies have shown the efficacy of mycophenolate mofetil (MMF) in improving calcineurin inhibitor (CI)-induced nephrotoxicity with concomitant reduction or withdrawal of CI. In this prospective study we assessed the long-term effect and safety of MMF. Thirty-two OLT recipients with significant renal impairment due to either cyclosporine A ( n=25) or tacrolimus ( n=7) were enrolled in this study. CIs were reduced stepwise by at least 70%. Mean serum creatinine had decreased from 2.63+/-0.39 to 1.74+/-0.34 mg/dl after 1 month, and this improvement was maintained within a follow-up period of 4.8+/-0.6 (range 3.1-6.0) years, without major immunological or non-immunological side effects. Of all participants, 88% showed a significant reduction, and 41% even a normalization, in their serum creatinine level. In addition, MMF conversion, within 6 months of OLT, appears to be crucial in order to improve or even normalize renal function. This study demonstrates the long-term efficacy and safety of MMF in OLT recipients with CI-induced nephropathy.

Adult↗