Topic
Methylamide
About: Methylamide is a research topic. Over the lifetime, 320 publications have been published within this topic receiving 4875 citations.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: The rate constant for the transition between the equatorial and axial conformations of N‐acetylalanyl‐N′‐methylamide has been determined from Langevin dynamics simulations with no explicit solvent, indicating that both collisional energy transfer with solvent and vibrational energy transfer between internal modes are important in the dynamics of barrier crossing for this system.
Abstract: The rate constant for the transition between the equatorial and axial conformations of N-acetylalanyl-N′-methylamide has been determined from Langevin dynamics (LD) simulations with no explicit solvent. The isomerization rate is maximum at collision frequency γ = 2 ps−1, shows diffusive character for γ ≥ 10 ps−1, but does not approach zero even at γ = 0.01 ps−1. This behavior differs from that found for a one-dimensional bistable potential and indicates that both collisional energy transfer with solvent and vibrational energy transfer between internal modes are important in the dynamics of barrier crossing for this system. It is suggested that conformational searches of peptides be carried out using LD with a collision frequency that maximizes the isomerization rate (i.e., γ ≈ 2 ps−1). This method is expected to be more efficient than either molecular dynamics in vacuo (which corresponds to LD with γ = 0) or molecular dynamics in solvent (where dynamics is largely diffusive).
1,092 citations
Journal Article•
TL;DR: The inhibitor N-[2R-2-(hydroxamidocarbonymethyl)-4-methylpentanoyl)]-L- tryptophan methylamide specifically blocks several matrix metalloproteases, enzymes which are thought to be involved in angiogenesis and suggest that inhibitors of these enzymes may be angiostatic agents.
Abstract: The inhibitor N-[2R-2-(hydroxamidocarbonymethyl)-4-methylpentanoyl)]-L- tryptophan methylamide specifically blocks several matrix metalloproteases, enzymes which are thought to be involved in angiogenesis. An extract of Walker 256 carcinoma in Hydron pellets implanted in the corneas of Sprague-Dawley rats was used to stimulate angiogenesis from the vessels of the limbus. Angiogenesis was graded visually as the distance penetrated into the cornea and the number of vessels generated. The vessel area was also measured by image analysis using Image 1 software. Continuous i.v. administration of N-[2-(hydroxamidocarbonymethyl)-4-methylpentanoyl)]- L-tryptophan methylamide at 32 mg/kg/day (n = 17) via syringe pump reduced vessel number [25.06 +/- 5.9 (SEM) compared to 65.33 +/- 9.0] and vessel area (26.14 +/- 3.2 mm2 compared with 40.96 +/- 4.6 mm2), but not distance penetrated, compared to vehicle-treated control eyes after 6 days. These results confirm the suspected role for matrix metalloproteases in angiogenesis and suggest that inhibitors of these enzymes may be angiostatic agents.
158 citations
147 citations
TL;DR: Structural parameters, derived from X-ray crystallographic data, have been compiled for 35 derivatives of amino acids, peptides, and related compounds, which contain the N-terminal benzyloxycarbonyl (Z) group, indicating that most conformations of Z-amino acid-N'-methylamides and of corresponding Boc derivatives have similar dihedral angles and relative energies.
Abstract: Structural parameters, derived from X-ray crystallographic data, have been compiled for 35 derivatives of amino acids, peptides, and related compounds, which contain the N-terminal benzyloxycarbonyl (Z) group. The geometry of the urethane moiety of this end group is closely similar to that of the tert-butoxycarbonyl (Boc) group, except for a relaxation of some bond angles because the Z group is sterically less crowded than the Boc group. For the same reason, the Z group has greater conformational flexibility. As a result, packing forces in the crystal may cause greater deformations of bond angles, resulting in larger variations of observed bond lengths and bond angles than in Boc-peptide crystals. The aromatic rings of the Z end groups tend to stack in crystals. Conformational energy calculations indicate that most conformations of Z-amino acid-N'-methylamides and of corresponding Boc derivatives have similar dihedral angles and relative energies, i.e. the nature of the N-terminal end group has little effect on the conformational preferences of the residue next to it. In particular, the computed fraction of molecules with a cis urethane (C-N) bond is similar for the two derivatives: 0.51 and 0.42 in Boc-Pro-NHCH3 and Z-Pro-NHCH3, respectively, and 0.02 in the two Ala derivatives. There exist several computed conformations of Z-Ala-NHCH3 and Z-Pro-NHCH3 in which the phenyl ring and the C-terminal methylamide group are close to each other. Because of favorable nonbonded interactions, such conformations are of low energy.
103 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2019 | 3 |
| 2018 | 2 |
| 2017 | 1 |
| 2016 | 3 |
| 2014 | 4 |