On the basis of these considerations, the effects of the Arg2 - Arg3 and Arg3 - Nal4 peptide bonds on the activity of FC131 have been investigated through the synthesis and evaluation
of the alkene analogues such as compounds 5 - 8 (Figure 6)[69].
Not exact matches
Selective hydrogenation is the key to producing valuable chemicals, for example, turning triple - bonded hydrocarbons called alkynes selectively into double - bonded
alkenes — starting materials for the synthesis
of plastics, fuels and other commercial products.
Ethylene (or IUPAC name ethene) is the simplest
alkene hydrocarbon, consisting
of four hydrogen atoms and two carbon atoms connected by a double bond.
The researchers showed that quantum mechanical tunneling greatly enhances the production rate
of hydroxyl radicals in
alkene ozonolysis reactions, which sever multiple bonds under atmospheric conditions.
Related research (Pereira HJ, et al., 2012) used two different lines
of evidence to explain the increase in the ratio
of anteiso — to iso - branched
alkenes that was observed during the transition from early to late stationary phase in M. luteus: structural studies
of a key enzyme involved in fatty acid biosynthesis in M. luteus (FabH, or ß - ketoacyl - ACP synthase III) and transcriptional (whole - genome microarray) studies
of M. luteus during different growth phases.
Selective hydrogenation is the key to producing valuable chemicals, for example, turning triple - bonded hydrocarbons called alkynes selectively into double - bonded
alkenes — starting materials for the synthesis
of plastics, fuels and other...
The effect
of a trans - locked Gly - Pro
alkene isostere on collagen triple helix stability.
Wiktelius D, Luthman K. Taking control
of P1, P1» and double bond stereochemistry in the synthesis
of Phe - Phe (E)-
alkene amide isostere dipeptidomimetics.
Both (E)-
alkene and (Z)- fluoroalkene analogues (5 and 6) with substitutions at the Arg2 - Arg3 dipeptide moderately inhibited SDF - 1 binding to CXCR4 with IC50 values
of 1.46 and 1.78 μM, respectively.
Peptide bond mimicry by (E)-
alkene and (Z)- fluoroalkene peptide isosteres: synthesis and bioevaluation
of alpha - helical anti-HIV peptide analogues.
It is now well known that a systematic replacement
of the planar peptide bond with an
alkene bioisostere is useful for the estimation
of the electrostatic effects and for the SAR evaluation
of peptide derivatives.
The replacement
of the Arg3 - Nal4 peptide bond with an (E)-
alkene isostere in compound 7 produced a negative effect on CXCR4 inhibitory activity, probably due to the lack
of H - bonding
of amide moiety and a different interaction
of pseudo -1,3-allylic strain between the Arg3 carbonyl group and the Nal4 side chain.
Oxidizing the end carbon atom
of a terminal
alkene to form an aldehyde, a process called anti-Markovnikov
alkene oxidation, is difficult because the reaction is energetically unfavorable.
The team now reports using directed evolution, an iterative process
of protein mutation and screening for activity, to identify amino acid substitutions that convert an enzyme into a predominantly anti-Markovnikov
alkene oxidation catalyst (Science 2017, DOI: 10.1126 / science.aao1482).
Markovnikov oxidation
of terminal
alkenes (left) to form ketones (center) is energetically favored, whereas anti-Markovnikov reactions leading to aldehydes are more difficult.
The main areas covered in this work booklet are: Alkanes
Alkenes Fractional distillation Cracking Polymerisation Burning Alcohols Organic acids Oil Within the booklet are a range
of different activities for students to work through to help them remember the content.
Topics include: States
of matter Diffusion Atomic Structure Separation Techniques Covalent Bonding Ionic Bonding Metallic Bonding Oxygen and Oxides Acids, Alkalis and Salts Rates
of Reaction Equilibrium Energetics Organic Chemistry - alkanes,
alkenes, alcohols, isomers, fractional distillation, cracking, polymerisation Chemistry in industry - Haber Process, Contact process, Extraction
of Metals
Smik, L., Cabedo - Sanz & Belt, S. T. Semi-quantitative estimates
of paleo Arctic sea ice concentration based on source - specific highly branched isoprenoid
alkenes: a further development
of the PIP25 index.
A team
of researchers in France has discovered an algal photoenzyme that catalyzes the decarboxylation
of free fatty acids to n - alkanes or -
alkenes in response to blue light.