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The biosynthesis of fatty acids begins with acetyl-CoA precursors that are brought together to make long straight chain lipids. Acetyl-CoA is produced in aerobic organisms by pyruvate dehydrogenase, an enzyme that has been shown to express a large, 2.3% isotope effect on the C2 site of pyruvate and a small fractionation on the C3 site. [19]
Prebiotic synthesis of amino acids, nucleobases, lipids, and other building blocks of protocells and metabolisms is still poorly understood. Proposed reactions that produce individual components such as the Strecker synthesis of amino acids, the formose reaction for the production of sugars, and prebiotic syntheses for the production of nucleobases.
Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.
Examples of various lipid species. Lipidomics is the large-scale study of pathways and networks of cellular lipids in biological systems. [1] [2] [3] The word "lipidome" is used to describe the complete lipid profile within a cell, tissue, organism, or ecosystem and is a subset of the "metabolome" which also includes other major classes of biological molecules (such as amino acids, sugars ...
The abundance of 15 N in some amino acids reflects an organism's position in a food web. This is due to the ways organisms metabolize different amino acids when they are consumed. Trophic amino acids (TrAAs) are first deaminated, meaning that the amino group is removed to produce an alpha-keto acid carbon skeleton.
Edman degradation, developed by Pehr Edman, is a method of sequencing amino acids in a peptide. [1] In this method, the amino-terminal residue is labeled and cleaved from the peptide without disrupting the peptide bonds between other amino acid residues.
Aromatic amino acids, excepting histidine, absorb ultraviolet light above and beyond 250 nm and will fluoresce under these conditions. This characteristic is used in quantitative analysis, notably in determining the concentrations of these amino acids in solution. [1] [2] Most proteins absorb at 280 nm due to the presence of tyrosine and ...
Backbone-dependent rotamer library for serine.Each plot shows the population of the χ 1 rotamers of serine as a function of the backbone dihedral angles φ and ψ. In biochemistry, a backbone-dependent rotamer library provides the frequencies, mean dihedral angles, and standard deviations of the discrete conformations (known as rotamers) of the amino acid side chains in proteins as a function ...