Structure, Mutagenesis, and QM:MM Modeling of 3-Ketosteroid Δ-Dehydrogenase from ─The Role of a New Putative Membrane-Associated Domain and Proton-Relay System in Catalysis.

3-Ketosteroid Δ-dehydrogenases (KstD) are important microbial flavin enzymes that initiate the metabolism of steroid ring A and find application in the synthesis of steroid drugs. We present a structure of the KstD from (AcmB), which contains a previously uncharacterized putative membrane-associated domain and extended proton-relay system. The experimental and theoretical studies show that the steroid Δ-dehydrogenation proceeds according to the Ping-Pong bi-bi kinetics and a two-step base-assisted elimination (E2cB) mechanism.

1,2-Hydrogenation and Transhydrogenation Catalyzed by 3-Ketosteroid Δ-Dehydrogenase from -Kinetics, Isotope Labelling and QM:MM Modelling Studies.

Bacteria and fungi that are able to metabolize steroids express 3-ketosteroid-Δ-dehydrogenases (KstDs). KstDs such as AcmB form Chol-1 catalyze the enantioselective 1α,2β-dehydrogenation of steroids to their desaturated analogues, e.g.

Variously Prepared Zeolite Y as a Modifier of ANFO.

In the presented research, we investigated Ammonium Nitrate Fuel Oil (ANFO), with the addition of variously modified zeolite Y as an attractive explosive. Analysis of both blasting tests and thermodynamic models of blasting properties led to the conclusion that the addition of zeolite Y enhanced the detonation properties of such prepared ANFO via the growth of the detonation pressure, temperature, compression energy, and heat of the explosion. Generally, the modification of ANFO with variously prepared zeolite Y also reduced the volume of (CO + NO) post-blast fumes.

Universal capability of 3-ketosteroid Δ-dehydrogenases to catalyze Δ-dehydrogenation of C17-substituted steroids.

Background: 3-Ketosteroid Δ-dehydrogenases (KSTDs) are the enzymes involved in microbial cholesterol degradation and modification of steroids. They catalyze dehydrogenation between C1 and C2 atoms in ring A of the polycyclic structure of 3-ketosteroids. KSTDs substrate spectrum is broad, even though most of them prefer steroids with small substituents at the C17 atom.

The efficient Δ-dehydrogenation of a wide spectrum of 3-ketosteroids in a broad pH range by 3-ketosteroid dehydrogenase from Sterolibacterium denitrificans.

Cholest-4-en-3-one Δ-dehydrogenase (AcmB) from Sterolibacterium denitrificans, a key enzyme of the central degradation pathway of cholesterol, is a protein catalyzing Δ-dehydrogenation of a wide range of 3-ketosteroids. In this study, we demonstrate the application of AcmB in the synthesis of 1-dehydro-3-ketosteroids and investigate the influence of reaction conditions on the catalytic performance of the enzyme. The recombinant AcmB expressed in E.

New lupeol esters as active substances in the treatment of skin damage.

The purpose of the research was to obtain new derivatives of natural triterpene lupeol and to evaluate their potential as active substances in the treatment of skin damage. Four new lupeol esters (propionate, succinate, isonicotinate and acetylsalicylate) and lupeol acetate were obtained using an eco-friendly synthesis method. In the esterification process, the commonly used hazardous reagents in this type of synthesis were replaced by safe ones.

Investigation of quaternary structure of aggregating 3-ketosteroid dehydrogenase from Sterolibacterium denitrificans: In the pursuit of consensus of various biophysical techniques.

In this work we analyzed the quaternary structure of FAD-dependent 3-ketosteroid dehydrogenase (AcmB) from Sterolibacterium denitrificans, the protein that in solution forms massive aggregates (>600 kDa). Using size-excursion chromatography (SEC), dynamic light scattering (DLS), native-PAGE and atomic force microscopy (AFM) we studied the nature of enzyme aggregation. Partial protein de-aggregation was facilitated by the presence of non-ionic detergent such as Tween 20 or by a high degree of protein dilution but not by addition of a reducing agent or an increase of ionic strength.

Demographical Profile and Spectrum of Multiple Malignancies in Children and Adults with Neurocutaneous Disorders.

Background/aim: Neurocutaneous disorders, also referred as phacomatoses, are congenital disorders manifesting at different ages with central nervous system and cutaneous abnormalities. Analysis of the demographic and clinical profile of patients with phacomatoses in the context of the incidence and spectrum of malignancy.

Materials And Methods: This is a retrospective analysis of 20 years of data in a single-center study in Poland.

Correction to: Bacterial steroid hydroxylases: enzyme classes, their functions and comparison of their catalytic mechanisms.

The published online version contains mistake in the author list. The correct presentation should have been "Rita Bernhardt" instead of "Rita Bernhard". There was a missing "t" on the original publication.

Bacterial steroid hydroxylases: enzyme classes, their functions and comparison of their catalytic mechanisms.

The steroid superfamily includes a wide range of compounds that are essential for living organisms of the animal and plant kingdoms. Structural modifications of steroids highly affect their biological activity. In this review, we focus on hydroxylation of steroids by bacterial hydroxylases, which take part in steroid catabolic pathways and play an important role in steroid degradation.

Electrocatalytic Hydroxylation of Sterols by Steroid C25 Dehydrogenase from Sterolibacterium denitrificans.

The electrochemically driven catalysis of the complex molybdoenzyme steroid C25 dehydrogenase (S25DH) from the β-Proteobacterium Sterolibacterium denitrificans is reported. S25DH catalyses the oxygen-independent regioselective hydroxylation of the tertiary C25 atom of sterols and also their derivatives. Cholest-4-en-3-one is a native substrate for S25DH, which produces 25-hydroxycholest-4-en-3-one as a product of catalytic turnover.