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Soluble Peptides (soluble + peptide)
Selected AbstractsATPASE ACTIVITY, SURFACE HYDROPHOBICITY, SULFHYDRYL CONTENT AND PROTEIN DEGRADATION IN REFRIGERATED SEABASS MUSCLE IN MODIFIED ATMOSPHERE PACKAGINGJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2004PAYAP MASNIYOM The effect of modified atmosphere packaging (80% CO2, 10% O2, 10% N2) on ATPase activity, surface hydrophobicity, sulfhydryl content and degradation of proteins in seabass muscle during storage at 4C was investigated. No changes in Ca2+ -, Mg2+ -, Mg2+ -Ca2+ -ATPase activities of natural actomyosin (NAM) in seabass slices kept under MAP were observed throughout the storage for up to 21 days (P > 0.05). However, a slightly increased Mg2+ -EGTA-ATPase was found. For seabass slices stored under air atmosphere, Ca2+ -ATPase activity decreased, whereas Mg2+ -EGTA-ATPase activity increased (P < 0.05) with a concomitant loss in Ca2+ -sensitivity. Lower decreases in total sulfhydryl content but higher increases in surface hydrophobicity were observed in samples stored under MAP, compared to those kept under air atmosphere. No marked autolytic degradation in samples kept under MAP was observed throughout the storage as monitored by no changes in myosin heavy chain, free ,-amino acid and trichloroacetic acid soluble peptide. Conversely, a considerable degradation was found in samples kept under air atmosphere, especially after 9 days of storage. Therefore, MAP is a promising means to retard the changes in muscle proteins, especially degradation. [source] In vitro transdermal iontophoretic delivery of leuprolide,mechanisms under constant voltage applicationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2003Charu Kochhar Abstract The transdermal iontophoretic delivery of Leuprolide, a nonapeptide LHRH agonist was studied with the aim of understanding the mechanisms of iontophoresis. Permeation studies were carried out at pH 4.5 and 7.2, at which the average ionic valence of the drug molecule was roughly 2 and 1, respectively. Heat-separated human epidermal membrane was subjected to constant voltage within the range of 250 to 1000 mV during the iontophoretic phase. Iontophoretic enhancement at pH 7.2 was greated than at 4.5. A model for iontophoretic enhancement was developed that takes into consideration the membrane alterations caused by iontophoresis depicted as increased porosity and the permeation through lipid pathways of the stratum corneum. Model-based evaluation yielded that first, the porosity increased with the applied voltage to as much as three times the original at 1000 mV. Second, the lipid pathways contributed approx. 20% to the total permeation during the passive phase. Third, the electro-osmotic flow contributed significantly to the enhancement and its direction was from anode to cathode at pH 7.2 and the opposite at pH 4.5. The magnitude of the electro-osmotic flow was at pH 4.5 somewhat lower than at pH 7.2. Addition of a negatively charged water soluble peptide, Acetyl leucine leucinolyl phosphate as an adjuvant led to twofold increase in the enhancement factor at pH 4.5 and a decrease in the magnitude of the electro-osmotic flow from cathode to anode. Repeated iontophoretic applications of 250 mV on the same skin specimen resulted in same enhancement every time and did not cause any barrier alterations when applied for 1 h every 24 h, which was not the case if the duration between the two iontophoretic applications was only 3 h. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:84,96, 2003 [source] Higher Soluble Amyloid , Concentration in Frontal Cortex of Young Adults than in Normal Elderly or Alzheimer's DiseaseBRAIN PATHOLOGY, Issue 4 2010Zoë Van Helmond Abstract Little is known about the relationship between soluble amyloid , (A,) and age. We have measured soluble and insoluble A, by enzyme-linked immunosorbent assay (ELISA) in post-mortem frontal cortex in normal brains (16,95 years) and AD. Insoluble A, increased with age, and was significantly higher in Alzheimer's disease (AD) than age-matched controls. However, levels of soluble A, declined with age and were significantly greater in younger adults than older adults with or without AD. In AD, insoluble : soluble A, ratio was much higher than in age-matched controls. The high levels of soluble A, in young adults included oligomeric species of A,1-42. These observations do not preclude A, oligomers as neurotoxic mediators of AD but suggest that if they are, the toxicity may be restricted to certain species (eg, ,-pleated protofibrillar species not detected by our assay) or takes decades to manifest. The dramatically increased insoluble : soluble A, in AD points to an altered dynamic equilibrium of A, in AD, reflecting both enhanced aggregation and continued overproduction or impaired removal of the soluble peptide in older age, when the concentration of this peptide should be declining. [source] In vitro haem solubility of red cell fraction of porcine blood under various treatmentsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2010Tong-Xun Liu Summary An in vitro peptic digestion at gastric pH 2.0 was used to assess the haem solubility of red cell fraction (RCF) of porcine blood derived samples. The in vitro haem solubility of the RCF decreased greatly in the denaturated form of haemoglobin. However, the native haemoglobin was susceptible to be hydrolysed by enzyme mixture of Flavourzyme and Alcalase. The in vitro digestion of the hydrolysates showed that the highest haem solubility was reached at degree of hydrolysis between 8.75% and 12.33%. The in vitro haem solubility was positively correlated with content of the highly soluble peptides with molecular weights ranged from 7.5 kDa to 1 kDa, but negatively with peptides fractions >7.5 kDa and <1 kDa, mostly due to the precipitation of the highly molecular weight fraction (>7.5 kDa) and part of small peptides (<1 kDa) with higher haem/peptide ratio, which was confirmed by gel filtration chromatograms and by the analysis of the precipitate at pH 2.0. [source] CX3CL1/fractalkine shedding by human hepatic stellate cells: contribution to chronic inflammation in the liverJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8a 2009Katia Bourd-Boittin Abstract Chemokines are the inflammatory mediators that modulate liver fibrosis, a common feature of chronic inflammatory liver diseases. CX3CL1/fractalkine is a membrane-associated chemokine that requires step processing for chemotactic activity and has been recently implicated in liver disease. Here, we investigated the potential shedding activities involved in the release of the soluble chemotactic peptides from CX3CL1 in the injured liver. We showed an increased expression of the sheddases ADAM10 and ADAM17 in patients with chronic liver diseases that was associated with the severity of liver fibrosis. We demonstrated that hepatic stellate cells (HSC) were an important source of ADAM10 and ADAM17 and that treatment with the inflammatory cytokine inter-feron-, induced the expression of CX3CL1 and release of soluble peptides. This release was inhibited by the metalloproteinase inhibitor batimastat; however, ADAM10/ADAM17 inhibitor GW280264X only partially affected shedding activity. By using selective tissue metalloprotease inhibitors and overexpression analyses, we showed that CX3CL1 was mainly processed by matrix metalloproteinase (MMP)-2, a metalloprotease highly expressed by HSC. We further demonstrated that the CX3CL1 soluble peptides released from stimulated HSC induced the activation of the CX3CR1-dependent signalling pathway and promoted chemoattraction of monocytes in vitro. We conclude that ADAM10, ADAM17 and MMP-2 synthesized by activated HSC mediate CX3CL1 shedding and release of chemotactic peptides, thereby facilitating recruitment of inflammatory cells and paracrine stimulation of HSC in chronic liver diseases. [source] Angiotensin converting enzyme inhibition of fish protein hydrolysates prepared from alkaline-aided channel catfish protein isolateJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2007Ann E Theodore Abstract Peptides derived from aquatic animals have been shown to have inhibitory activity against angiotensin converting enzyme (ACE), which is a key enzyme behind elevated blood pressure. In this study a catfish protein isolate was prepared and hydrolyzed to 5%, 15% and 30% degrees of hydrolysis (% DH) and soluble peptides separated from the total hydrolysate. The hydrolysate and its soluble peptide fraction were studied separately. Increased hydrolysis produced smaller peptides, with the smallest peptides remaining in the soluble fraction. Both hydrolysates and its soluble fraction had high ACE inhibition activities, from 70% to 90.6%, depending on fraction and % DH. Results suggested that there is not a simple relationship between average peptide size and extent of % DH and ACE inactivation, but clearly the soluble fraction of the hydrolysate, containing the smallest peptides, is responsible for most of the ACE inhibition activity of the hydrolysate. Hydrolysates prepared from a pure and uniform catfish protein isolate substrate do therefore show a potential for ACE inhibition and may find use as bioactive ingredients. Copyright © 2007 Society of Chemical Industry [source] Copper Homeostasis: The Role of Cellular TransportersNUTRITION REVIEWS, Issue 9 2001Edward D. Harris Ph.D. Copper transport at the cellular level is achieved by a coordinate series of interactions between passive and active membrane transport proteins, vesicles, and soluble peptides. Knowing the function of each component of this complex network has made the task of delineating the mechanism of intracellular copper homeostasis achievable. [source] | |||||||||||||