Amino acids stability

Proteins are biopolymers formed by one or more continuous chains of covalently linked amino acids. Hydrogen bonds between non-adjacent amino acids stabilize the so-called elements of secondary structure, a-helices and / —sheets. A number of secondary structure elements then assemble to form a compact unit with a specific fold, a so-called domain. Experience has shown that a number of folds seem to be preferred, maybe because they are especially suited to perform biological protein function. A complete protein may consist of one or more domains. 

Wagschal, K., Tripet, B., Lavigne, P., Mant, C., and Hodges, R. S. (1999). The role of position a in determining the stability and oligomerization state of a-helical coiled coils 20 amino acid stability coefficients in the hydrophobic core of proteins. 

Scorpionid secretions represent a mixture of neurotoxic polypeptide toxins, proteolytic and hemolytic enzymes (phospholipases A, acetylcholinesterases, ribonucleases, hyaluronidases), and biogenic amines (serotonin, tryptamine, histamine). The polypeptide toxins (the so-called scorpamines) contain fewer than 40 or 60-76 mostly alkaline and aromatic amino acids stabilized by four disulfide bridges.20 96... 

Neurotoxins of scorpions especially represent ion channel toxins that mainly affect sodium and potassium channels. Several compounds represent neurotoxins that are directed selectively against insects.97 Na+ channel-specific a-, (3-, and 7-toxins are composed of 58-76 amino acids and contain four stabilizing disulfide bridges.98 The well-studied K+ channel-specific toxins (divided into at least nine distinct peptide subfamilies) bind to the extracellular face of the channel and comprise 29-39 amino acids stabilized by 3-4 disulfide bridges.99 Various Ca2+ channel scorpion toxins, antimicrobial peptides, and short insectotoxins active on Cl channels have been found.96... 

Chloride channels have a completely different structure from potassium channels [15]. The dimeric structure has two ion pathways, one formed by each monomer. The ion pathway does not run straight through the membrane, but is U-shaped. Amino acids stabilize the ion in the pathway by forming direct interactions with the chloride atom via hydrogen bond donors, just as the carbonyl groups in the selectivity filter of potassium channels stabilize the potassium cation. 

Metathesis/Transmetallation of Amino Acid Stabilized Nanoparticles... 

The MRTs of individual humus fractions also vary, as can be seen from Table 8. The MRT of the original soil (Melfort silt loam) was 870 years whereas the MRTs of individual fractions ranged from 25 to 1410 years. For both humic and fulvic acids, the acid hydrolyzable fractions (6A HCl for 18 hours) had lower MRTs than the nonhydrolyzable fractions. This result is in accord with expectations, because the hydrolyzable material would include the carbon of readily decomposable substrates (e.g., carbohydrates and amino acids). Stability of the major humus fractions followed the order humin = humic acid > fulvic acid (Campbell et al., 1967a). 

Baxter, J.H. Free amino acid stability in reducing sugar systems, J. Food Sci., 60,405,1995. 

Potassium cetyl phosphate Steareth-10 allyl ether/acrylates copolymer stabilizer, hair cleansers TEA-lauroyl collagen amino acids stabilizer, hair colors Diethylhexyl 2,6-naphthalate stabilizer, hair preps. 

Drays MK, Armentrout PB, Oomens J, Schafer M. IR spectroscopy of cationized aliphatic amino acids stability of charge-solvated structure increases with metal cation size. Int J Mass Spectrom. 2010 297 18-27. 

Schmidt J, Kass SR (2013) Zwitterion vs neutral structures of amino acids stabilized by a negatively charged site infrared photodissociation and computations of proline-chloride anion. J Phys Chem A 117 4863-4869... 

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