Sericin Serine

Serial basin test Sericin Sericin gum Senate [12174-53-7] Serinal... 

Internal Structure of Silk and Linen. Triangular-shaped silk filaments (called brins and composed of the protein fibroin) are embedded in a second protein (sericin) to form the bave unit. Microscopic examination of fabrics woven with the silk bave unit and subsequently cleaned of sericin reveals paired brin filaments. Fibroin contains 16 amino acids, and more than 80 of the polymer is composed of glycine, alanine, and serine only (6). Their small side groups allow chains of these amino acids to pack together closely to form the crystalline portions of the fiber. The bulkier amino acids, such as tyrosine, disrupt crystal order and produce the amorphous areas of the internal structure of the fiber. 

Both fibrion and sericin are protein substances built up of 16-18 amino acids, out of which only glycine, alanine, serine and tyrosine make up the largest part of the silk fibre (see Table 1.8) and the remaining amino acids containing bulky side groups are not significant. The chemical stmcture of fibrion and sericin for four... 

Enzyme which can hydrolyse the sericin is classified as proteolytic enzymes [63-65]. The proteolytic enzymes cleave the peptide/amide linkages and convert them into amino acid. Mainly there are three types of proteolytic enzymes such as zinc protease (e.g. carboxy peptidase A), serine protease (Chymotrypsin, Trypsin, Thrombin) and thiol protease (acts as cystine residue in the protein). The function of proteolytic enzymes in their degree of degumming depends on the pH of the bath and the optimum activity is found to be different at different pH for different enzymes. 

Sericin, the protein that binds the pairs of fibroin filaments as they emerge from the silkworm, and which may have a role in dehydrating the fibroin and encouraging its crystallisation, has a markedly different composition and structure to that of fibroin. It is largely amorphous and is rich in serine (—32%), aspartic acid (—14%) and glycine (—13%) there is a much greater proportion of residues with polar and/or bulky side-chains. The predominance of these polar, hydrophilic groups means that sericin is readily soluble in hot water. 

L-Serine isolated from a sulfuric acid hydrolyzate of sericine, a protein component of silk (lat. sericus silken) by E. Cramer. Structure by the same author. Synthesis E. Fischer and H. Leuchs, 1902. 

Silk fibers, which are obtained from the secretion of the silkworm, are double filaments that are enclosed by a coating of a gum (sericin) as they are secreted. The amino acid sequence of the silk protein was shown to be (glycine-serine-glycine-alanine-glycine-alanine). The polypeptide chains are bound into antiparallel pleated )ff-sheet structures by hydrogen bonding. The structures are also held together by van der Waal forces. ... 

Rapeseedamidopropyl benzyidimonium chloride Rapeseedamidopropyl epoxypropyl dimonium chloride Rapeseedamidopropyl ethyidimonium ethosulfate Resorcinol acetate Ricinoleamide DEA Ricinoleamide MEA Ricinoleamide MIPA Ricinoleamidopropyl betaine Ricinoleamidopropyl dimethylamine Ricinoleamidopropyl dimethylamine lactate Ricinoleamidopropyl ethyidimonium ethosulfate Ricinoleamidopropyl trimonium chloride Ricinoleamidopropyl trimonium methosulfate Saffloweramidopropyl ethyidimonium ethosulfate Sericin D-Serine DL-Serine L-Serine Silicone quaternium-2 Silicone quaternium-3 Silicone quaternium-5 Silicone quatemium-6 Silicone quaternium-7 Silicone quaternium-8 Silicone quaternium-9 Silk powder Sodium acrylate/vinyl alcohol, copolymer Sodium carrageenan Sodium caseinate Sodium chondroitin sulfate Sodium cocoyl hydrolyzed collagen Sodium cocoyl hydrolyzed keratin Sodium cocoyl hydrolyzed rice protein Sodium cocoyl hydrolyzed soy protein Sodium glyceryl oleate phosphate Sodium isethionate Sodium lauraminopropionate Sodium lauriminodipropionate Sodium lauroamphohydroxypropylsulfonate Sodium lauroamphopropionate... 

Sericin consists of a family of serine-rich polypeptides with various molecular weights. 

Serine was first isolated from sericin by Cramer in 1865. Most proteins contain about 4-8% serine. In phosphoproteins (casein, phosvitin) serine, like threonine, is a carrier of phosphoric acid in the form of 0-phosphoserine. The carbohydrate component of glycoproteins may be bound 0-glycosidically through the hydroxyl group of serine and/or threonine [cf. 10.1.2.1.1 (K-casein) and 13.1.4.2.4]. 

Silkworm silk, the silk from the cocoon of B. mori contains at least two major fibroin proteins, light and heavy chains, 25 and 325 kDa, respectively. These core fibers are encased in a sericin coat, a family of gluelike proteins that holds two fibroin fibers together to form the composite fibers of the cocoon case to protect the growing worm. Silkworm cocoon silk production, known as sericulture, produces high yields as the larvae can be maintained in high densities. The core sequence repeats in the fibroin heavy chain from B. mori include alanine-glycine repeats with serine or tyrosine [334]. It has been widely used as biomedical sutures and in textile production. 

Fibroin and sericin differ in amino acid composition. Fibroin is composed of a total of 18 amino acids, mainly glycine, alanine, serine, and tyrosine. The major component of sericin is serine. 

S. is a thread spun by the silk moth or silk worm (Bombyx mori). It is composed of two fibroin fibers surrounded by a thin layer of sericin. Fibroin is a ->protein that consists mainly (ft 90%) of the - amino acids glycine, alanine, serine and tyrosine, while sericin consists of 37% serine, and 14.7% each of glycine and aspartic acid. Both contain small portions of other amino acids. S. is highly crystalline (60%). 

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