Glutathione as a Prebiotic Answer to alpha-Peptide Based Life.

The energetics of peptide bond formation is an important factor not only in the design of chemical peptide synthesis, but it also has a role in protein biosynthesis. In this work, quantum chemical calculations at 10 different levels of theory including G3MP2B3 were performed on the energetics of glutathione formation. The strength of the peptide bond is found to be closely related to the acid strength of the to-be N-terminal and the basicity of the to-be C-terminal amino acid. It is shown that the formation of the first peptide activates the amino acid for the next condensation step, manifested in bacterial protein synthesis where the first step is the formation of an N-formylmethionine dipeptide. The possible role of glutathione in prebiotic molecular evolution is also analyzed. The implications of the thermodynamics of peptide bond formation in prebiotic peptide formation as well as in the preference of alpha- instead of beta- or gamma-amino acids are discussed. An empirical correction is proposed for the compensation of the error due to the incapability of continuum solvation models in describing the change of the first solvation shell when a peptide bond is formed from two zwitterions accompanied by the disappearance of one ion pair

Pd-Catalyzed microwave-assisted synthesis of phosphonated 13α-estrones as potential OATP2B1, 17β-HSD1 and/or STS inhibitors

Novel 2- or 4-phosphonated 13α-estrone derivatives were synthesized via the Hirao reaction. Bromo regioisomers (2- or 4-) of 13α-estrone and its 3-benzyl or 3-methyl ether were reacted with diethyl phosphite or diphenylphosphine oxide using Pd(PPh3)4 as catalyst under microwave irradiation. The influence of the new compounds on the transport function of the organic anion transporting polypeptide OATP2B1 was investigated by measuring Cascade Blue uptake. Derivatives bearing a 3-benzyl ether function displayed substantial submicromolar OATP2B1 inhibitory activity. The inhibitory effects of the compounds on human placental steroid sulfatase (STS) and 17β-hydroxysteroid dehydrogenase type 1 isozyme (17β-HSD1) were investigated by in vitro radiosubstrate incubation methods. None of the test compounds inhibited the STS markedly. The structure–activity relationship evaluation revealed that 2-substituted 3-hydroxy derivatives are able to inhibit the 17β-HSD1 enzyme with submicromolar IC50 values. Dual OATP2B1 and 17β-HSD1 inhibitors have been identified

Folyóirat-referátumok = From the Literature

Tüdőgyógyászat: 1. C. L. Bjornson - D. W. Jonson: Pseudocroup = Crou

Folyóirat-referátumok = From the literature

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Folyóirat-referátumok = From the literature

Fertőző betegségek: 1. J. B. Bines [et al.]: A csecsemőkori invaginatio rizikófaktorai Vietnamban és Ausztráliában: az adenovírus keveredett gyanúba, nem a rotavírus = Risk factors for intussusception in infants in Vietnam and Australia: adenovirus implicated, but not rotavirus Sportorvostan: 1. A. M. Luks [et al.]: Egy ultramaraton-kerékpározó tüdőödémája az Amerikán át verseny során = An ultracyclist with pulmonary edema during the bicycle race across Americ

Folyóirat-referátumok = From the literature

Alvászavar: 1. Chr. Proukakis [et al.]: Vége(?) a medve általi üldöztetésnek = Exit, pursued by a bear Diabetológia: 1. A. Hekkala - M. Knip - R. Veijola: Ketoacidosis diagnózis 1-es típusú diabeteses gyermekek között Észak-Finnországban. Időbeli változások 20 év alatt = Ketoacidosis at diagnosis of type 1 diabetes in children in Northern Finland. Temporal changes over 20 years) Gyermekgyógyászat: 1. S. Nurko [et al.]: A gyermekkori székrekedés PEG3350-kezelése = PEG3350 in the treatment of childhood constipatio