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Pepsin Digestion (pepsin + digestion)
Selected AbstractsPyridinium Cross-Links in Bone of Patients with Osteogenesis Imperfecta: Evidence of a Normal Intrafibrillar Collagen PackingJOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2000Ruud A. Bank Ph.D. Abstract The brittleness of bone in patients with osteogenesis imperfecta (OI) has been attributed to an aberrant collagen network. However, the role of collagen in the loss of tissue integrity has not been well established. To gain an insight into the biochemistry and structure of the collagen network, the cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) and the level of triple helical hydroxylysine (Hyl) were determined in bone of OI patients (types I, III, and IV) as well as controls. The amount of triple helical Hyl was increased in all patients. LP levels in OI were not significantly different; in contrast, the amount of HP (and as a consequence the HP/LP ratio and the total pyridinoline level) was significantly increased. There was no relationship between the sum of pyridinolines and the amount of triple helical Hyl, indicating that lysyl hydroxylation of the triple helix and the telopeptides are under separate control. Cross-linking is the result of a specific three-dimensional arrangement of collagens within the fibril; only molecules that are correctly aligned are able to form cross-links. Inasmuch as the total amount of pyridinoline cross-links in OI bone is similar to control bone, the packing geometry of intrafibrillar collagen molecules is not disturbed in OI. Consequently, the brittleness of bone is not caused by a disorganized intrafibrillar collagen packing and/or loss of cross-links. This is an unexpected finding, because mutant collagen molecules with a random distribution within the fibril are expected to result in disruptions of the alignment of neighboring collagen molecules. Pepsin digestion of OI bone revealed that collagen located at the surface of the fibril had lower cross-link levels compared with collagen located at the inside of the fibril, indicating that mutant molecules are not distributed randomly within the fibril but are located preferentially at the surface of the fibril. [source] CHARACTERIZATION AND COMPARISON OF COLLAGENS EXTRACTED FROM THE DIGESTIVE TRACT AND SKIN OF A JAPANESE AMBERJACK SERIOLA QUINQUERADIATAJOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2009MAKI NISHIMOTO ABSTRACT Collagen was extracted from the digestive tract and skin of a Japanese amberjack (Seriola quinqueradiata) by acid extraction and limited pepsin digestion. The amounts of collagen solubilized from the digestive tract were smaller than those from the skin. Based on the solubility in NaCl solution, electrophoretic and peptide map patterns, and amino acid composition, the main digestive tract collagen was identified as type I, having characteristics different from those of the body wall collagen in cyclostome intestine. Further, the degree of hydroxylation of prolyl and lysyl residues in the type I collagen of the digestive tract is significantly higher than that of the skin. Collagen preparations from the digestive tract have a higher ratio of type V collagen than those from the skin. Hence, the digestive tract collagen differs from that in the skin in the degree or property of intermolecular crosslinking, posttranslational modification, and molecular species composition. PRACTICAL APPLICATIONS Partial hydrolyzate of gelatin, in other word collagen peptide, has gained popularity as a food ingredient, as it has been suggested to have health benefits, such as improvement of skin and joint conditions. Recently, attention toward collagen derived from marine origin such as fish skin increased because of the outbreak of bovine spongiform encephalopathy. Large amounts of the digestive tract, stomach, intestine and adhesion tissues are generated by fishery industries and most of them are by-products of low value. Although these organs are also rich in collagen, the collagen in fish digestive tract has not been characterized. The present study demonstrates that the collagen in digestive tract differs from the skin collagen in the solubility, posttranslational modification and molecular species composition. These facts suggest that modified collagen peptides might be obtained from the digestive tract. [source] IN VITRO DIGESTIBILITY OF CHINESE TARTARY BUCKWHEAT PROTEIN FRACTIONS: THE MICROSTRUCTURE AND MOLECULAR WEIGHT DISTRIBUTION OF THEIR HYDROLYSATESJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2006XIAONA GUO ABSTRACT Our previous study showed that in vitro pepsin digestibility of Chinese tartary buckwheat protein was relatively low compared to those of other edible seeds. In vitro pepsin digestibilities of four protein fractions of tartary buckwheat, microstructure and molecular weight (MW) distributions of hydrolysates were investigated. In vitro pepsin digestion assay showed that the digestibilities of tartary buckwheat protein fractions were albumin (81.20%), globulin (79.56%), prolamin (66.99%) and glutelin (58.09%). Scanning electron microscopy showed that albumin and globulin fractions were digested by pitting from the outer surface to the inner part and were more digestible, while prolamin and glutelin fractions resisted digestion because only the outer surfaces of their protein bodies were digested and the interior was protected. MW distribution of the hydrolysates from the four protein fractions was determined by high-performance liquid chromatography. The hydrolysates of albumin mainly consisted of polypeptides with lower MW. The hydrolysates of glutelin had larger polypeptides together with small and medium-sized peptide fractions. [source] Immunochemical and Immunohistochemical Identification of a Minor Collagen in Raw Muscles of Decapod MollusksJOURNAL OF FOOD SCIENCE, Issue 4 2000S. Mizuta ABSTRACT: Approximately 10% of total muscle collagen in 6 decapod molluskan species was recovered as minor collagenous fractions by limited pepsin digestion and differential salt precipitation. The main alpha components (,1) in these fractions showed similar peptide maps of V-8 protease and lysyl endopeptidase digests to each other and had reactivity to the antiserum against the al component of the minor collagen (named Type SQ-II) from Todarodes pacificus muscle in immunoblot analysis. These results suggested that the minor molecular species of collagen corresponding to Type SQ-II of Todarodes pacificus was widely distributed in the mantle muscle of decapod mollusks. In addition, immunohistochemical experiments revealed that Type SQ-II collagen distributed mainly in intramuscular thin connective tissue (endomysium), suggesting the functional importance of this molecule to the development of meat texture of decapod mollusks. [source] A possible CD1a Langerhans cell,mast cell interaction in chronic hyperplastic candidosisJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 6 2007Ahmed Ali Aims:, T lymphocyte,antigen-presenting cell (APC) interaction plays a central role in T lymphocyte activation and APC maturation. We therefore studied the CD1a-positive Langerhans cells with respect to receptor activator of nuclear factor kappa B ligand (RANKL)-positive cells in chronic hyperplastic candidosis (CHC). Materials and methods:, Tissue sections of CHC were compared with leukoplakia and healthy oral mucosa using RANKL and CD1a monoclonal antibodies in an avidin,biotin peroxidase complex protocol. Two different antigen-retrieval protocols, pepsin preincubation and Tris,EDTA heat treatment, were used. Results:, CD1a-positive Langerhans cells were in healthy and leukoplakia epithelium found in the middle layer, but in CHC in all layers of the epithelium, at the basement membrane and as mononuclear round cells in the lamina propria. Use of pepsin digestion enabled studies of mast cells and their activation in the form of degranulation of RANKL. Conclusions:, The numerical, morphological and topographical versatility of the CD1a-positive Langerhans cells in CHC can be clarified by dendritic cell (DC) recruitment into the epithelium. RANK-positive and RANKL-sensitive DCs have ample opportunity to interact with local T lymphocytes. Use of an optimized antigen-retrieval protocol enabled demonstration of an active engagement (degranulation) of mast cells, which represent a rapidly available source of soluble RANKL. [source] The immunosuppressive activity and solution structures of ubiquitin fragmentsBIOPOLYMERS, Issue 6 2009ukasz Jaremko Abstract Recently, ubiquitin was suggested as a promising anti-inflammatory protein therapeutic. We found that a peptide fragment corresponding to the ubiquitin50,59 sequence (LEDGRTLSDY) possessed the immunosuppressive activity comparable with that of ubiquitin. CD and NMR spectroscopies were used to determine the conformational preferences of LEDGRTLSDY in solution. The peptide mixture, obtained by pepsin digestion of ubiquitin, was even more potent than the intact protein. Although the peptide exhibited a well-defined conformation in methanol, its structure was distinct from the corresponding 50,59 fragment in the native ubiquitin molecule. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 423,431, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | |||||||||||||