Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pepsin (3.6 nmol) was detected by the following three-step procedure: (i) reaction with a 20-fold molar excess of BO-IMI (a fluorophore containing a reactive imidazole group) in the presence of a 150-fold molar excess of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and 2% sodium dodecyl sulfate; (ii) gel filtration (spin column) to remove most of the residual BO-IMI; and (iii) capillary electrophoresis with laser-induced fluorescence detection. For the latter step, 8.5 x 10(-7) of the original sample was injected. BO-IMI/EDC targets phosphomonoesters and does not label albumin (prior knowledge). Progressive dephosphorylation of pepsin with acid phosphatase reduced its labeling with BO-IMI. Thus, the BO-IMI, as intended, labels the phosphate group on pepsin. Such BO-IMI labeling should be useful in general for studying phosphoproteins and phosphopeptides.
Anal Biochem 1995 Sep 20
PMID:Phosphate-specific fluorescence labeling of pepsin by BO-IMI. 750 26

The ability of cathepsin D, chymosin, pepsin and renin to produce endothelin-1 (ET-1) from proendothelin-1 (proET-1) was compared. No significant conversion was observed when proET-1 was incubated with up to 1 U of renin for 15 min at 37 degrees C. Cathepsin D generated, as well as degraded, ET-1 rapidly. Net production of ET-1 reached a maximum when 0.003 U of cathepsin D was used, and about 16% of the initial proET-1 was detected as ET-1 by HPLC. Pepsin up to 1 U converted proET-1 into ET-1 dose-dependently with a maximum of 71% conversion. A further increase of the amount of pepsin in the reaction mixture produced nonspecific cleavage of ET-1. Less than 10% of ET-1 remained in the presence of 15 U of pepsin. Chymosin also generated ET-1 dose-dependently, and a complete conversion was obtained at 1 U of enzyme. Greater than 1 U of chymosin only slightly degraded ET-1; at least 80% of ET-1 was still present when 15 U of chymosin was included in the assay. Other properties associated with the conversion of proET-1 into ET-1 by chymosin were investigated. Similar to authentic ET-1, the product of chymosin treatment caused contraction of isolated rabbit aortic rings, and pre-incubation of chymosin with pepstatin A abolished this contractile response.(ABSTRACT TRUNCATED AT 250 WORDS)
Int J Pept Protein Res 1993 Sep
PMID:Conversion of proendothelin-1 into endothelin-1 by aspartylproteases. 822 77

Pepsin contains, in a single chain, two conformationally homologous lobes that are thought to have been evolutionarily derived by gene duplication and fusion. We have demonstrated that the individual recombinant lobes are capable of independent folding and reconstitution into a two-chain pepsin or a two-chain pepsinogen (Lin, X., et al., 1992, J. Biol. Chem. 267, 17257-17263). Pepsin spontaneously inactivates in neutral or alkaline solutions. We have shown in this study that the enzymic activity of the alkaline-inactivated pepsin was regenerated by the addition of the recombinant N-terminal lobe but not by the C-terminal lobe. These results indicate that alkaline inactivation of pepsin is due to a selective denaturation of its N-terminal lobe. A complex between recombinant N-terminal lobe of pepsinogen and alkaline-denatured pepsin has been isolated. This complex is structurally similar to a two-chain pepsinogen, but it contains an extension of a denatured pepsin N-terminal lobe. Acidification of the complex is accompanied by a cleavage in the pro region and proteolysis of the denatured N-terminal lobe. The structural components that are responsible for the alkaline instability of the N-terminal lobe are likely to be carboxyl groups with abnormally high pKa values. The electrostatic potentials of 23 net carboxyl groups in the N-terminal domain (as compared to 19 in the C-terminal domain) of pepsin were calculated based on the energetics of interacting charges in the tertiary structure of the domain. The groups most probably causing the alkaline denaturation are Asp11, Asp159, Glu4, Glu13, and Asp118.(ABSTRACT TRUNCATED AT 250 WORDS)
Protein Sci 1993 Sep
PMID:Conformational instability of the N- and C-terminal lobes of porcine pepsin in neutral and alkaline solutions. 840 Dec 24

Felt prepared from polyglycolide (PGA) polymer fibers was pasted with fibrin glue for prevention of postoperative pulmonary fistula, and its effects were evaluated. The subjects were 90 patients who underwent thoracotomy and were expected to develop air leakage between March 1990 and the end of 1993. The felt sheet was simply pasted in position in 67 patients, applied and fixed by suturing in 7, and sutured and pasted in 16. The duration of air leakage in the three groups were 4.6 +/- 4.1, 3.9 +/- 4.9, and 3.2 +/- 3.8 days, respectively. According to the surgical procedure employed, the duration of air leakage was 5.0 +/- 4.0 days in 41 patients who underwent pulmonary lobectomy, 5.0 +/- 4.3 days in 5 patients who underwent segmentectomym, 2.6 +/- 3.1 days in 26 cases who underwent partial pneumonectomy, and 4.9 +/- 4.0 days in the 14 cases who underwent bulla resection. In terms of disease, the leakage time was 4.6 +/- 4.2 days in patients with emphysema, 0.6 +/- 1.2 days in those with diffuse pulmonary fibrosis, 0.7 +/- 0.9 days in those with Infectious disease, 4.8 +/- 4.2 in those with lung cancer, 1.5 +/- 1.5 days in those with benign lung tumor, and 3.8 +/- 2.7 days in those with metastatic lung tumors. The procedure had no side-effect on liver or kidney function. No infection was observed even after decortication for empyema. The use of felt prevented excessive shrinking of the lung due to over-suturing. Therefore, intraoperative application of a PGA felt sheet was considered to be an effective method for prevention of pulmonary fistula.
Nihon Kyobu Geka Gakkai Zasshi 1995 Sep
PMID:[Clinical experience of the combined use of polyglycolide non-woven felt with fibrin glue to prevent postoperative pulmonary fistula]. 853 Aug 38

The effect of diet, human milk or formula, on gastric function (lipase and pepsin activity, pH, and volume) and intragastric digestion of fat was assessed in 28 appropriate for gestational age preterm infants (gestational age, 28.9 +/- 1.4, 29.1 +/- 0.9, 29.5 +/- 0.6 wk; birth weight, 1.00 +/- 0.14 to 1.18 +/- 0.07 kg). The infants were fed either human milk (n = 11), SMA Super Preemie formula (n = 9), or Similac, Special Care formula (n = 8). Fasting and postprandial activity of digestive enzymes, pH, and gastric volume (measured before or during 50 min after gavage feeding) did not differ as a function of diet among the three groups of infants. Gastric lipase output, 23.1 +/- 5.1, 28.3 +/- 6.6, and 22.5 +/- 6.4 (U/kg of body weight) in human milk-, SMA SP-, or Similac SC-fed infants was comparable to the gastric lipase output of healthy adults fed a high fat diet (22.6 +/- 3.0). Pepsin output was, however, significantly lower (597 +/- 77, 743 +/- 97, and 639 +/- 142 U/kg of body weight) in human milk-, SMA SP-, and Similac SC-fed infants) than in healthy adults (3352 +/- 753 U/kg). The hydrolysis of dietary fat was 1.7-2.5-fold higher (p < 0.01) in human milk-fed infants than in infants fed either formula. We conclude that differences in type of feeding, i.e. different fatty acid profiles (long chain or medium chain triglycerides), different emulsions (natural or artificial), and different fat particle sizes do not affect the level of activity of gastric enzymes. However, the triglyceride within milk fat globules appears to be more accessible to gastric lipase than that within formula fat particles. We suggest that the contribution of gastric lipase to overall fat digestion might be greater in the newborn (a period of pancreatic insufficiency) than in the adult.
Pediatr Res 1996 Sep
PMID:Effect of human milk or formula on gastric function and fat digestion in the premature infant. 886 80

Early studies of murine experimental autoimmune encephalomyelitis (EAE) induced with myelin basic protein (MBP) divide various mouse strains into either "susceptible" or "resistant" phenotypes. Resistance is defined as lack of encephalitogenic responses after active immunization or adoptive transfer. It is now becoming clear that this unresponsiveness is not due to the inability of T cells to recognize MBP in the context of major histocompatibility complex (MHC) gene products. Using various manipulations, many laboratories are able to induce severe EAE in these strains. We previously reported that a combination of adoptive transfer and subsequent challenge of the recipients with MBP could overcome the resistance in many mouse strains (Shaw et al.: J Neuroimmunol 39:139-150, 1992). This approach now enables us to identify the encephalitogenic epitope and T cell receptor V beta usage in a prototype strain, C57BL/6 (B6). Pepsin-digested MBP fragments first located a major T cell epitope in a polypeptide containing residues 44-88. Overlapping synthetic peptides narrowed this epitope to p60-80. Truncated peptides from the carboxyl- or amino-terminus further mapped a minimal peptide to p67-76. This encephalitogenic epitope appears to be unique to B6 mice. Independent encephalitogenic T cell clones specific for this epitope were also generated. Of six such clones analyzed, five different TCR V beta's were found. Whether unbiased usage of encephalitogenic TCR V beta gene segments in B6 mice is related to its EAE resistant phenotype is not clear at this point.
J Neurosci Res 1996 Sep 15
PMID:Induction of myelin basic protein-specific experimental autoimmune encephalomyelitis in C57BL/6 mice: mapping of T cell epitopes and T cell receptor V beta gene segment usage. 889 80

An autosomal dominant mutation in the COL2A1 gene was identified in a child with the Kniest form of spondyloepiphyseal dysplasia. A C to T transition at nucleotide 35 of exon 12 changed the codon GCG for alanine 102 of the triple helical domain of alpha 1(II) chains of type-II collagen to GTG for valine. The transition also introduced a GT dinucleotide into exon 12. Analysis of cDNA prepared from Kniest cartilage showed that in vivo the transition resulted in an alternatively spliced mRNA that lacked the 213' nucleotides from exon 12. The cartilage cDNA contained approximately equal amounts of normal cDNA and shortened mutant cDNA. The deletion of 21 nucleotides from the mutant cDNA maintained the translational reading frame but resulted in the loss of alanine 102 to lysine 108, which interrupted the repetitive glycine-X-Y triplet sequence required for formation of the triple helix. Type-II collagen molecules containing one or more mutant chains were expected, therefore, to contain interrupted triple helices with a short amino-terminal helical domain A and a large carboxy-terminal helical domain B. Kniest cartilage contained a reduced amount of pepsin-solubilized type-II collagen that consisted of overmodified alpha 1(II) chains. Peptide mapping showed that the overmodifications extended to the carboxy terminus of the alpha 1(II) chains. Pepsin digestion also yielded shortened alpha 1(II) chains corresponding to helical domain B. Kniest chondrocytes cultured in alginate beads produced type-II collagen that was not stably incorporated into the pericellular matrix. This study highlights the importance of dominant negative mutations of COL2A1 in producing Kniest dysplasia.
J Orthop Res 1996 Sep
PMID:Alternative splicing of exon 12 of the COL2A1 gene interrupts the triple helix of type-II collagen in the Kniest form of spondyloepiphyseal dysplasia. 889 63

Pepsin secretion was studied in vivo in the primary culture of isolated secretory gastric mucosa cells of the frog (Rana ridibunda). The injection of animals with carbacholin (200 micrograms/100 g weight) or histamine (100 micrograms/100 g weight) or addition of the hormones (100 microM) into the incubation medium of isolated gastric cells significantly increased pepsin activity. In vitro, preliminary addition of the specific antagonists of these hormones to the incubation medium (1 microM atropine or 100 microM cimetidine) completely suppressed the effects of hormones. The effect of histamine is season-dependent. Combined injection or simultaneous addition to incubation medium of isolated cells of carbacholin and histamine caused mutual potentiation of their effects. In this case, the quantitative response of the cells exceeded the theoretical sum of the stimulatory effects of each of these two hormones alone. According to electrophoresis, the hormones cause quantitative changes in isozyme spectrum of proteolytic enzymes but do not significantly affect their qualitative characteristics.
Biokhimiia 1996 Sep
PMID:[Mutually potentiating effect of joint action of carbacholine and histamine on secretion and the isoenzyme spectrum of pepsin from frog gastric mucosa cells]. 899 86

The interactions of type VI collagen have been investigated, using solid phase binding assays, with two components of the fibrillin-containing microfibrils, the elastin-binding protein, MAGP-1 and its structural relative MAGP-2. Both native and pepsin-treated forms of type VI collagen specifically bound to MAGP-1 but not to MAGP-2. Pepsin type VI collagen was shown to block the binding of MAGP-1 to native type VI collagen indicating that the major MAGP-1-binding site was in the triple-helical region of the molecule. MAGP-1 was found not to bind to collagens I, III, and V. Affinity blotting of pepsin-treated type VI collagen showed that MAGP-1 binding was specific for the collagenous domain of the alpha3(VI) chain. Decorin and biglycan were found not to inhibit the interaction of pepsin-treated type VI collagen with MAGP-1, indicating that its binding site on the collagen is not close to that for the proteoglycans. Reduction and alkylation of disulfide bonds in MAGP-1 did not destroy its type VI collagen-binding properties, indicating that the binding site was likely to be in the cysteine-free, N-terminal domain of MAGP-1. Interestingly, the interaction of MAGP-1 with type VI collagen was inhibited by tropoelastin, suggesting that the binding sites for tropoelastin and type VI collagen may be in the same domain of MAGP-1. A peptide, corresponding to amino acids 29-38 of MAGP-1, was found to inhibit the interactions of MAGP-1 with type VI collagen and tropoelastin. The results suggest that the peptide may contain the binding sequences for both type VI collagen and tropoelastin, and thus that these two proteins may share the same binding site on MAGP-1. The interactions of MAGP-1 with type VI collagen and tropoelastin were both determined to be of moderately high affinity, with Kd values of 5.6 x 10(-7) M and 2.6 x 10(-7) M, respectively. The findings indicate that MAGP-1 may mediate a molecular interaction between type VI collagen microfibrils and fibrillin-containing microfibrils, structures which are often found in close proximity to each other in a wide range of extracellular matrices.
J Biol Chem 1997 Sep 05
PMID:Microfibril-associated glycoprotein-1 (MAGP-1) binds to the pepsin-resistant domain of the alpha3(VI) chain of type VI collagen. 927 43

The objective of this study was to characterize and evaluate the performance of various fiber-matrix composite systems by studying the mechanical, thermal, and physical properties of the fiber and matrix components, and by studying the fiber-matrix interface adhesion strength using both microbond and fragmentation methods. The composites studies were poly(L-lactic acid) (PLLA) matrix reinforced with continuous fibers of either nonabsorbable AS4 carbon (C), absorbable calcium phosphate (CaP), poly(glycolic acid) (PGA), or chitin. Carbon and CaP single fibers had high Young's moduli and failed in a brittle manner. PGA and chitin single fibers had relatively lower Young's moduli and relatively higher ductility. Upon in vitro hydrolysis, CaP fibers retained 17% of their tensile strength and 39% of their Young's modulus after 12 h, PCA fibers retained 10% of their tensile strength and 52% of their Young's modulus after 16 days, and chitin fibers retained 87% of their tensile strength and 130% of their Young's modulus after 25 days. PLLA films had much lower strength and Young's moduli, but much higher ductility relative to the single fibers. Using the microbond method, the initial fiber-matrix interfacial shear strength (IFSS) of C/PLLA and CaP/PLLA microcomposites was 33.9 and 12.6 MPa, respectively. Upon in vitro hydrolysis, C/PLLA retained 49% of IFSS after 15 days and CaP/PLLA retained 46% of IFSS after 6 h. Using a fiber fragmentation method, the initial IFSS of C/PLLA, CaP/PLLA, and chitin/ PLLA was 22.2, 15.6, and 28.3 MPa, respectively. The performance of carbon fibers and C/PLLA composites was superior to the other fibers and fiber/PLLA systems, but the carbon fiber was nonabsorbable. CaP had the most suitable modulus of the absorbable fibers for fixing cortical bone fracture, but its rapid deterioration of mechanical properties and loss of IFSS limits its use. PGA and chitin fibers had suitable mechanical properties and their retention for fixing cancellous bone fractures, but likely had insufficient stiffness for applications such as bone plates for fixing cortical bone fractures.
J Biomed Mater Res 1997 Sep 15
PMID:Fiber-matrix interface studies on bioabsorbable composite materials for internal fixation of bone fractures. I. Raw material evaluation and measurement of fiber-matrix interfacial adhesion. 929 62


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