Isolation and partial characterization of a soluble mucin in human pancreatic juice

1991 ◽  
Vol 69 (8) ◽  
pp. 566-571
Author(s):  
S. P. Lee ◽  
Y. S. Choong ◽  
H. Z. Park

Morphological and histochemical abnormalities in pancreatic mucin occur in many pancreatic disorders. However, the composition of pancreatic mucin is poorly understood. Purified mucin was isolated from pure pancreatic juice by sequential chromatography on Sepharose CL-2B and CL-4B followed by CsCl density gradient ultracentrifugation. The mucin preparation consists of 24% protein and 73% carbohydrate. Reduction of the macromolecule (> 2 × 106) by mercaptoethanol resulted in the formation of subunits of molecular weight 500 000 and released several small molecular weight proteins, including a glycoprotein of an average molecular weight of 116 000. Cellulose acetate electrophoresis separated the mucin into three species of different staining properties for periodic acid-Schiff reagent and Alcian blue, suggesting the presence of microheterogeneity with respect to sulphation and sialation. Threonine, serine, and proline composed 48% of the total amino acids, while the oligosaccharide moiety contained N-acetylglucosamine, N-acetyl-galactosamine, fucose, galactose, sialic acid, and sulphate. We also detected the presence of C16:0 and C18:0 fatty acids which were probably noncovalently bound to the pancreatic mucin.Key words: pancreas, mucin, glycoprotein, cystic fibrosis.

1982 ◽  
Vol 205 (1) ◽  
pp. 225-233 ◽  
Author(s):  
Norman Fleming ◽  
Michael Brent ◽  
Ramiro Arellano ◽  
Janet F. Forstner

Rat submandibular mucin (RSM) was purified by acid precipitation, then alcohol precipitation of the 30000g supernatant of gland homogenate, followed by column chromatography on Sephadex G-200. The mucin, which was eluted in the void volume, had an amino acid profile typical of a salivary mucus glycoprotein with high proportions of threonine, serine and proline (48.8% of total amino acids), and low proportions of aromatic and basic amino acids. It consisted of 63% (w/w) carbohydrate, which was shown by g.l.c. analysis to contain N-acetylglucosamine, N-acetylgalactosamine, galactose, sialic acid and fucose in the proportions 1.0:3.4:2.6:3.1:1.2. After staining of the mucin with periodic acid/Schiff reagent, analytical equilibrium ultracentrifugation in a CsCl density gradient produced a symmetrical peak of buoyant density 1.449g/ml, without evidence of protein contaminants. Sedimentation velocity centrifugation revealed a major periodate/Schiff-positive component (S020,w 5.06) with an associated shoulder of slower sedimenting material, suggesting polydispersity in the size of the mucin. Our findings suggest that the RSM purified in these studies has a molecular weight between 200000 and 1×106. Antibody to RSM was prepared in a rabbit and produced a single precipitin line on immunoelectro-osmophoresis with the mucin. Immunofluorescence studies showed that the antibody localized only to submandibular acinar cells and confirmed that these cells were the source of RSM. The antibody was not directed towards the blood-group-A determinant (terminal N-acetylgalactosamine) present in the mucin.


1977 ◽  
Author(s):  
J. Pindyck ◽  
M. W. Mosesson ◽  
D. Bannerjee ◽  
D. Galanakis

The structure and subunit composition of chicken fibrinogen(ϕ) have been investigated. Dodecyl sulfate gel electrophoresis of unreduced specimens revealed a single ϕ band with a molecular weight of approximately 320,000. ϕ and fibrin specimens were also electrophoresed after reduction with dithiothreitol, and after crosslinking of unreduced specimens in the presence of Factor Xllla. Chromatographically separated S-sulfo chains were also studied after reptilase or thrombin treatment,and certain samples were stained with periodic acid Schiff reagent(PAS). Chicken Aα chains weresmaller than human Aα chains (54,500 vs.70,900, respectively) but, like mammalian Aα chains, they possessed a reptilase and thrombin sensitive site, were PAS negative,and undergo Factor XIIIa catalyzed α-polymer formation. The sizes of chicken Bβ and γ chains were nearly thesame as their mammalian counterparts, (i. e. 60,000 and 49,000 respectively) ; both types of chains were PAS positive. Chicken Bβ chains possessed a slowly reactive thrombin sensitive site apparently corresponding to the one in human ϕ; the chicken β chains, like mammalian β chains, did not undergo Factor XIIIa catalyzed cross-linking. Like mammalian γ chains, chicken γ chains could undergo Factor XIIIa catalyzed γ-γ dimerization and did not possess thrombin or reptilase sensitive sites. These findings indicate that the chicken fibrinogen molecule is composed of three pairs of disulfide-bridged chains corresponding in most respects to mammalian fibrinogen chains.


1981 ◽  
Vol 195 (2) ◽  
pp. 389-397 ◽  
Author(s):  
D A Wiginton ◽  
M S Coleman ◽  
J J Hutton

Adenosine deaminase was purified 3038-fold to apparent homogeneity from human leukaemic granulocytes by adenosine affinity chromatography. The purified enzyme has a specific activity of 486 mumol/min per mg of protein at 35 degrees C. It exhibits a single band when subjected to sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, non-denaturing polyacrylamide-gel electrophoresis and isoelectric focusing. The pI is 4.4. The enzyme is a monomeric protein of molecular weight 44000. Both electrophoretic behaviour and molecular weight differ from those of the low-molecular-weight adenosine deaminase purified from human erythrocytes. Its amino acid composition is reported. Tests with periodic acid-Schiff reagent for associated carbohydrate are negative. Of the large group of physiological compounds tested as potential effectors, none has a significant effect. The enzyme is specific for adenosine and deoxyadenosine, with Km values of 48 microM and 34 microM respectively. There are no significant differences in enzyme function on the two substrates. erythro-9-(2-Hydroxy non-3-yl) adenine is a competitive inhibitor, with Ki 15 nM. Deoxycoformycin inhibits deamination of both adenosine and deoxyadenosine, with an apparent Ki of 60-90 pM. A specific antibody was developed against the purified enzyme, and a sensitive radioimmunoassay for adenosine deaminase protein is described.


1988 ◽  
Vol 66 (5) ◽  
pp. 367-373 ◽  
Author(s):  
Sum P. Lee ◽  
Jane F. Nicholls ◽  
Anthony M. Roberton ◽  
Han Z. Park

Partially purified native-pig gastric mucus and purified pig gastric mucin, prepared by column chromatography and caesium chloride (CsCl) density-gradient ultracentrifugation, were subjected to pepsin digestion. The products of peptic digestion were chromatographed on Sepharose CL-2B, and fractions were assayed for carbohydrate by the periodic acid – Schiff reaction. The polymeric gastric mucin in the purified mucin samples was readily degraded by pepsin. In sharp contrast, the polymeric mucin in the partially purified mucus was relatively resistant to pepsin digestion. In 45 min, pepsin degraded 40% of the polymeric mucin in the purified samples, whereas it produced no significant degradation (<10%) in the partially purified mucus samples. In partially purified gastric mucus, treated with CsCl but not fractionated by ultracentrifugation, digestion with pepsin was also slow and incomplete. This showed that differences in susceptibility between partially purified and purified preparations are not due to the chaotropic effects of CsCl. In addition, the recombination of low-density nonmucin fractions in CsCl ultracentrifugation with the mucin also resisted pepsin digestion. Finally, we have shown that the low-density fractions in mucus exhibited a strong inhibitory effect of peptic activity in vitro. We conclude that under our experimental conditions, pepsin has little effect on partially purified mucus, and our findings indicate an inhibitor of peptic digestion is present in native gastric mucus. It is likely, but unproven, that this inhibitor is a noncovalently bound lipid present in the low-density fraction.


1983 ◽  
Vol 31 (6) ◽  
pp. 709-716 ◽  
Author(s):  
M R Green

Proteins in colostrum and skimmed milk from humans and mice were separated by electrophoresis on polyacrylamide gels and stained with Coomassie blue (CB), Ethyl-Stains-all (ESA), and periodic acid-Schiff (PAS) to investigate changes that may occur in milks throughout lactation. In mouse colostrum but not in mature mouse milk, a PAS-positive protein of apparent molecular weight of 60,000 stained prominently blue with ESA. A protein in human milk with a molecular weight of 68,000 stained similarly but was present throughout lactation. The intensity of blue staining of these minor proteins in milk approached that obtained with casein phosphoproteins. The metachromatic dye ESA stains phosphoproteins and sialic acid-rich glycoproteins blue to blue-green. Removal of phosphorus from the former and sialic acid from the latter results in those proteins staining red with ESA. The intensity of blue staining of the 60,000 and 68,000 Mr proteins was diminished but not lost following treatment with phosphatase. It was eliminated following neuraminidase digestion of the mouse protein and mild acid hydrolysis of the human protein. Coomassie blue staining of the proteins was not affected by these procedures. Following electrophoresis of milk and milk fractions in a non-sodium dodecyl sulfate-containing system, the proteins were identified by their characteristic staining properties with ESA and isolated.


1961 ◽  
Vol 113 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Melvin H. Kaplan ◽  
Frederick D. Dallenbach

Using fluorescent antibody methods, deposits of bound gamma globulin, as determined in unfixed washed sections of auricular appendages from rheumatic hearts, were noted in a significant number (18 per cent) of 100 specimens studied. Such deposits were observed in myofibers, sarcolemma, interstitial connective tissue, and vessel walls. Albumin and fibrin were generally found absent from these sites. Control hearts from normal and pathologic material, including postmortem and biopsied specimens, in general, did not reveal such deposits. These various tissue sites which contained bound gamma globulin frequently exhibited evidence of alteration as indicated both by enhanced affinity for eosin and by strongly positive reaction with the periodic acid-Schiff reagent, and appeared comparable in some cases to "fibrinoid." Bound gamma globulin was not observed in cellular or stromal components of Aschoff lesions, nor was the occurrence of Aschoff lesions correlated with presence of bound gamma globulin. It is suggested that deposition of gamma globulin and the eosinophilic alteration associated with such deposition are related to certain of the pathologic changes of rheumatic heart disease. The nature of such deposits of gamma globulin was considered from immune and non-immune points of view.


1972 ◽  
Vol 50 (3) ◽  
pp. 292-298
Author(s):  
V. N. Katiyar ◽  
B. L. Dinh

The incorporation of 14C-leucine into the microsomal proteins of nephrotic rat kidney was much higher than that in the microsomal proteins of the normal rat kidney. When the newly synthesized microsomal proteins were analyzed by acrylamide gel electrophoresis, it was found that the higher incorporation of 14C-leucine in nephrotic rat kidney was mostly due to an increase in the biosynthesis of a tissue protein which migrated in the electrophoretic zone between serum albumin and transferrin. This protein did not react with rabbit antiserum to normal rat serum and was stained with periodic acid – Schiff reagent. It was believed to be excreted in the urine of nephrotic rats in great quantity and was easily identified as a distinct band in electrophoregrams of urine from these rats.


1976 ◽  
Vol 54 (8) ◽  
pp. 707-716 ◽  
Author(s):  
I. Jabbal ◽  
D. I. C. Kells ◽  
G. Forstner ◽  
J. Forstner

Goblet cell mucin (GCM) has been purified for the first time from mucosal scrapings of human small intestine. Proteolytic enzymes and organic solvents were avoided during the isolation procedure. The mucin was purified by Sepharose 4B and 2B column chromatography of high-speed supernatant fractions. The most purified fraction was compared with rat intestinal GCM. The two were similar with respect to chemical composition, antigenic features, and polyacrylamide disc gel electrophoresis. The major chemical differences included a higher hexosamine–fucose and hexosamine – sialic acid ratio in human mucin. The two mucins showed strong concentration dependence in sedimentation velocity studies. Human mucin at a concentration of 0.2 to 1.5 mg protein per millilitre gave multiple associated peaks with variable s0 values (10.8–36.6). Rat mucin, in contrast, gave a constant (although polydisperse) pattern with s0 = 15.15. To explore these differences both mucins were stained with periodic acid – Schiff reagent and subjected to band ultracentrifugation at concentrations of 0.6–1.9 μg protein per millilitre. At this low concentration, rat mucin did not change in its sedimentation characteristics. In contrast, human GCM produced a single peak with s0 = 37.9. Thus dilution abolished polydispersity in the human but not the rat mucin, suggesting that intermolecular bonding forces in the human mucin are weaker.


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