Search results for "Arcos"

Impact of compatible solutes on the mechanical properties of fibronectin: a single molecule analysis

2003

The influence of ectoine and sarcosine on the mechanical properties of surface bound fibronectin has been investigated by means of force microscopy. Single molecule stretching experiments of fibronectin molecules reveal that ectoine and sarcosine increase the tendency of the polypeptide to coil, thus decreasing its apparent persistence length. This behavior can be explained by means of the preferential exclusion model implying that the osmolytes are expelled from the protein surface due to the increase in chemical potential of the denatured, i.e. stretched, state forcing the protein into a more compact structure. Detailed analysis of the unfolding forces, which are extracted from the succes…

Polypept(o)ides: Hybrid Systems Based on Polypeptides and Polypeptoids.

2015

Polypept(o)ides combine the multifunctionality and intrinsic stimuli-responsiveness of synthetic polypeptides with the "stealth"-like properties of the polypeptoid polysarcosine (poly(N-methyl glycine)). This class of block copolymers can be synthesized by sequential ring opening polymerization of α-amino acid N-carboxy-anhydrides (NCAs) and correspondingly of the N-substituted glycine N-carboxyanhydride (NNCA). The resulting block copolymers are characterized by Poisson-like molecular weight distributions, full end group integrity, and dispersities below 1.2. While polysarcosine may be able to tackle the currently arising issues regarding the gold standard PEG, including storage diseases i…

Synthesis and Sequential Deprotection of Triblock Copolypept(o)ides Using Orthogonal Protective Group Chemistry

2014

The synthesis of triblock copolymers based on polysarcosine, poly-N-ε-t-butyloxycarbonyl-l-lysine, and poly-N-ε-t-trifluoroacetyl-l-lysine by ring-opening polymerization of the corresponding α-amino acid N-carboxyanhydrides (NCAs) is described. For the synthesis of N-ε-t-butyloxycarbonyl-l-lysine (lysine(Boc)) NCAs, an acid-free method using trimethylsilylchloride/triethylamine as hydrochloric acid (HCl) scavengers is presented. This approach enables the synthesis of lysine(Boc) NCA of high purity (melting point 138.3 °C) in high yields. For triblock copolypept(o)ides, the degree of polymerization (Xn ) of the polysarcosine block is varied between 200 and 600; poly-N-ε-t-butyloxycarbonyl-l-…

Impact of Branching on the Solution Behavior and Serum Stability of Starlike Block Copolymers.

2019

The size control of nanomedicines for tumor diagnosis and therapy is of high importance, since it enables or disables deep and sufficient tumor penetration. Amphiphilic star-shaped block copolypept(o)ides offer substantial promise to precisely adjust the hydrophobic core and the hydrophilic corona, independent of each other, and therefore simultaneously control the size dimension in the interesting size range from 10 to 30 nm. To gain access to core-shell structures of such sizes, 3-arm and 6-arm PeptoStars, based on poly(gamma-tert-butyloxycarbonyl-L-glutamate)-b-polysarcosine (pGlu(OtBu)-b-pSar), were prepared via controlled living ring-opening polymerization (ROP) of the corresponding N-…

GARCÍA BAÑO, Ricardo. Prólogo de CALVO LÓPEZ, José. Arcos en esquina en el Renacimiento español. Función, forma y construcción

2020

El turismo enológico articulador del territorio : La ruta del vino Utiel-Requena

2014

Catalysis in glycine N-methyltransferase: testing the electrostatic stabilization and compression hypothesis.

2006

Glycine N-methyltransferase (GNMT) is an S-adenosyl-l-methionine dependent enzyme that catalyzes glycine transformation to sarcosine. Here, we present a hybrid quantum mechanics/molecular mechanics (QM/MM) computational study of the reaction compared to the counterpart process in water. The process takes place through an SN2 mechanism in both media with a transition state in which the transferring methyl group is placed in between the donor (SAM) and the acceptor (the amine group of glycine). Comparative analysis of structural, electrostatic, and electronic characteristics of the in-solution and enzymatic transition states allows us to get a deeper insight into the origins of the enzyme's c…

Towards sarcosine determination in urine for prostatic carcinoma detection

2019

Abstract Sarcosine, a potential biomarker for prostate cancer, can be detected in a solid state enzyme based biosensor using sarcosine oxidase, with particle immobilised reagents. A novel fusion protein of the fluorescent protein, mCherry, sarcosine oxidase (SOx), and the polypeptide R5 (R52-mCherry-SOx-R5-6 H), was explored, which allowed self-immobilization on silica microparticles and long-term (90 days +) retention of activity, even at room temperature. In contrast, commercial wildtype SOx lost activity in a few days. A silica-R52-mCherry-SOx-R5-6H microparticle sensor for determination of sarcosine in urine, linked the SOx coproduct, H2O2, to a measurement catalysed by horseradish pero…

A head-to-head comparison of poly(sarcosine) and poly(ethylene glycol) in peptidic, amphiphilic block copolymers

2015

Abstract In this work we compare chemical and solution properties, like critical aggregate concentrations (CAC) and hydrodynamic radii of aggregates based on either poly(ethylene glycol) or poly(sarcosine) block copolymers in aqueous solution. The amine functionalized, hydrophilic polymers poly(sarcosine) (degree of polymerization, X n  = 100 and 200) and PEG (X n  = 121 and 242) of comparable hydrodynamic volume were used to initiate the ring opening polymerization of α-amino acid- N -carboxyanhydrides based on ɣ-benzyl- l -glutamate (Glu(OBn)) or e-carboxybenzyl- l -lysine (Lys(Z)). The second, hydrophobic block was kept at a degree of polymerization of 25 and 50 to enable a direct compar…

Poly-sarcosine and poly(ethylene-glycol) interactions with proteins investigated using molecular dynamics simulations

2018

Nanoparticles coated with hydrophilic polymers often show a reduction in unspecific interactions with the biological environment, which improves their biocompatibility. The molecular determinants of this reduction are not very well understood yet, and their knowledge may help improving nanoparticle design. Here we address, using molecular dynamics simulations, the interactions of human serum albumin, the most abundant serum protein, with two promising hydrophilic polymers used for the coating of therapeutic nanoparticles, poly(ethylene-glycol) and poly-sarcosine. By simulating the protein immersed in a polymer-water mixture, we show that the two polymers have a very similar affinity for the…