Amino acids pearl

Tanaka, S., Hatano, H., Suzue, C. Biochemical studies on pearl. VII. Fractionation and terminal amino acids of conchiolin. J. Biochem. (Tokyo) 47, 117 (1960)... 

Malleshi, N. G. and Klopfenstein, C. F. (1998a). Nutrient composition and amino acid contents of malted sorghum, pearl millet and finger millet and their milling fractions. J. Food Sci. Technol. 35,247-249. 

It is well known that well-ordered (3-chitin (a polysaccharide) associated with a less ordered protein in the (3-sheet conformation is the main component of nacreous organic matrix in shell. The amino acid sequence of such proteins is very similar to those of silk fibroins. Indeed, the amino acid sequence of a major protein from the nacreous shell layer of the pearl oyster resembles that of spidroin (Sudo et al., 1997 Weiner and Traub, 1980). The question of whether silk-like proteins play an important role in shell formation is raised. When Falini et al. (1996) did the experiment with the proteins from the shell, they assembled a substrate in vitro that contained (3-chitin and natural silk fibroin and concluded that the silk fibroin may influence ion diffusion or the accessibility to the chi tin surface or both. Furthermore, cryo-TEM study of the structure of the Atrina shell nacreous organic matrix without dehydration... 

The amidic bonds within amino acids can be also used to effect the organization of polymers into superstructures (Fig. 10). Thus, the formation of artificial helices on the basis of assembling polymers has been described by use of poly(acetylenes) bearing pendant L-valine side-chains. [71,72] Two effects are important for the association of these ladder-type polymers into double-stranded helices (a) the reduction of conformational freedom by the poly(acetylene) chain with respect to a conventional alkyl-chain and (b) the selective association of the L-valine residues by specific hydrogen bonding. An AFM image of the associates on a fiat surface demonstrates the presence of a string-pearl structure reminiscent of natural DNA. 

Some polypeptide chains fold into two or more compact regions that may be connected by a flexible segment of polypeptide chain, rather like pearls on a string. These compact globular units, called domains, range in size from about 30 to 400 amino acid residues. For example, the extracellular part of CD4, the cell-surface protein on certain cells of the immune system to which the human immunodeficiency virus (HIV) attaches itself, comprises four similar domains of approximately 100 amino acids each (Figure 3.47). Often, proteins are found to have domains in common even if their overall tertiary structures are different. 

Amino acid Quinoa seed Barley pearled Soybean raw Wheat durum... 

Importantly, salt-induced peptide formation could provide an abiotic route for the formation of peptides directly from amino acids in concentrated NaCl solutions containing copper ions. Montmorillonite and similar minerals apparently promote the condensation reaction that could have taken place in evaporating tidal pools -Darwin s warm little ponds - where the required salty brine solutions were easily available. Obviously, this is a likely and hence a credible prebiotic scenario. There might a pearl hidden beneath muddy waters. Besides, it is fascinating to assume that the primitive enolase enzyme known to be a highly conserved ancient enzyme could have evolved in an RNA-peptide world. Enolase catalyzes the for enantio-selective carbon-carbon bond addition of water to phosphoenol pyruvate to yield D-2-phospho-glycerate. 

There is clearly a considerable difference between the pearl necklace and decorated micelle models, which may in part relate to the differences between the proteins, in particular the fact that BSA has a more restricted conformation because of disulphide linkages. However the most important difference is that in the pearl necklace model the polypeptide chain is believed to pass through micelles of constant size as opposed to around micelles of variable size in the decorated micelle model. However it is interesting that for the decorated micelles formed from the fragments S and L and the whole molecule the numbers of SDS molecules per amino acid residue are surprisingly uniform (0.45 (S), and 0.49 (L), and 0.48 (W)) and very close to the values in the flexible helix model stabilized by hydrogen bonding proposed by Lundahl et al. [110]. 

Less research has been carried out on millets than on other cereals. Nutritional quality is one area of priority. Like other cereals, millet has low contents of essential amino acids. For example, pearl millet contains in the order of 3 g lysine/100 g protein, whereas the World Health Organization recommends a minimum of 5.5 g/100 g. On the plus side, millets do not contain gluten proteins, so they are safe for those with celiac disease. Millets are low in certain minerals, including calcium. 

Pearl contains mostly calcium carbonate, ranging from ca. 81-95%, depending on source species, natural or cultured. It also contains ca. 6-13% organic substances that include 16 amino acids (leucine, methionine, alanine, phenylalanine, glycine, aspartic acid, glutamic acid, proline, serine, etc.) and a small amount of taurine numerous trace minerals, and so on. (hu jiangsu national). ... 

Pedant s point. The pearls of actual proteins are amino acids. The two-pearl protein model I am discussing is more properly called an amide . 

You already know that they are actually fragments of amino acids. They are not whole amino acids because some of their atoms have been used up to make the peptide links between them. What remains are called residues . That is, each pearl is an amino acid residue , more formally a peptide residue , with a chemical personality determined by the atoms that remain after the links to its neighbours are formed. Each residue is identified by an abbreviation of the name of its parent amino acid and its numerical location counted along the chain from one end. 

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