scholarly journals Purification and characterization of a cholesterol-binding protein from human pancreas

1982 ◽  
Vol 207 (3) ◽  
pp. 573-582 ◽  
Author(s):  
A Sziegoleit

The protein composition of human intestinal lavage fluids was analysed by electroimmunoassay. In addition to secretory immunoglobulin A and other components that were antigenically related to serum proteins, a number of gut-specific proteins were detected. One of these was found to exhibit the capacity of binding sodium deoxycholate and cholesterol. After isolation of this cholesterol-binding protein from intestinal fluids, immunohistochemical studies utilizing a specific antiserum indicated the pancreas to be the organ of its synthesis. The protein was subsequently purified from necrobiotic pancreas tissues and was found to be composed of a single polypeptide chain with a mol. wt. of 28 000 and an isoelectric point of pH4.9. The deoxycholate binding capacity determined by gel chromatography in the presence of [3H]deoxycholate was calculated to be approx. 24 mol of deoxycholate/mol of protein. In the intestinal fluids the protein appeared to be present in firm association with cholesterol, phospholipids, triacylglycerols and bile salts as a macromolecular protein-lipid complex. The possibility is raised that the pancreas-derived, cholesterol-binding protein may fulfil a function as an intestinal ‘lipoprotein’.

1984 ◽  
Vol 219 (3) ◽  
pp. 735-742 ◽  
Author(s):  
A Sziegoleit

A cholesterol-binding protein was previously isolated from human pancreas [Sziegoleit (1982) Biochem. J. 207, 573-582] and shown to consist of a single polypeptide chain with an apparent Mr of 28 000 and an isoelectric point of pH 4.9. In further investigations, a proteolytic activity was observed to be present in preparations of this protein. The enzyme activity was not dissociable from the cholesterol-binding protein. It decreased in the presence of sodium dodecyl sulphate or urea parallel to degradation of the protein, indicating autodegradation in the presence of these denaturants. Glucagon digestion studies indicated the carbonyl bond of alanine to be a favoured site of the enzymic cleavage. The proteinase was inactive against chromogenic substrates relatively specific for elastase, trypsin and chymotrypsin, but was found to cleave benzyloxycarbonylalanine p-nitrophenyl ester efficiently. The enzyme was inactivated by phenylmethanesulphonyl fluoride and was thus classified as a serine proteinase. Autoradiographic studies demonstrated binding to serum alpha 1-antitrypsin and alpha 2-macroglobulin in a similar manner to that observed with other pancreatic endo-proteinases. The collective results indicate that the isolated protein, provisionally named ‘cholesterol-binding pancreatic proteinase’, is a novel proteinase of the human pancreas. Quantitative measurements indicate that it comprises 4-6% of total protein in pancreatic secretions.


1983 ◽  
Vol 61 (9) ◽  
pp. 1035-1041 ◽  
Author(s):  
D. Bellabarba ◽  
S. Bédard ◽  
J. -G. Lehoux

The electrophoretic mobility and the sedimentation coefficient were determined in partially purified preparations of both rat liver cytosol and serum triiodothyronine (T3)-binding proteins. Crude cytosol and serum, each labeled with [125I]T3, were filtered through a Sephadex G-100 column. The cytosol yielded a single T3-binding peak, whereas three binding components were recognized in the serum. Protamine sulfate precipitated the cytosol T3-binding protein, but had no effect on the serum T3-binders. The cytosol protein and the three binding proteins from serum were analyzed by polyacrylamide gel electrophoresis and sucrose density gradient centrifugation. The cytosol binder migrated as a single peak on gel electrophoresis with an Rf of 0.53, whereas the serum proteins had Rfs between 0.27–0.33. The sedimentation coefficient of the cytosol protein was 6.3 S, whereas it was 4.1 S for the major binding protein of the serum. These data indicate that: (i) preliminary purification by gel chromatography is a useful step for better characterization of the T3-binding proteins of the cytosol and serum; (ii) the cytosol binder is an acidic protein with completely different properties from those of the serum T3-binding proteins.


1999 ◽  
Vol 145 (2) ◽  
pp. 279-289 ◽  
Author(s):  
Ping Lin ◽  
Yong Yao ◽  
Robert Hofmeister ◽  
Roger Y. Tsien ◽  
Marilyn Gist Farquhar

We previously demonstrated that CALNUC, a Ca2+-binding protein with two EF-hands, is the major Ca2+-binding protein in the Golgi by 45Ca2+ overlay (Lin, P., H. Le-Niculescu, R. Hofmeister, J.M. McCaffery, M. Jin, H. Henneman, T. McQuistan, L. De Vries, and M. Farquhar. 1998. J. Cell Biol. 141:1515–1527). In this study we investigated CALNUC's properties and the Golgi Ca2+ storage pool in vivo. CALNUC was found to be a highly abundant Golgi protein (3.8 μg CALNUC/mg Golgi protein, 2.5 × 105 CALNUC molecules/NRK cell) and to have a single high affinity, low capacity Ca2+-binding site (Kd = 6.6 μM, binding capacity = 1.1 μmol Ca2+/μmol CALNUC). 45Ca2+ storage was increased by 2.5- and 3-fold, respectively, in HeLa cells transiently overexpressing CALNUC-GFP and in EcR-CHO cells stably overexpressing CALNUC. Deletion of the first EF-hand α helix from CALNUC completely abolished its Ca2+-binding capability. CALNUC was correctly targeted to the Golgi in transfected cells as it colocalized and cosedimented with the Golgi marker, α-mannosidase II (Man II). Approximately 70% of the 45Ca2+ taken up by HeLa and CHO cells overexpressing CALNUC was released by treatment with thapsigargin, a sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) (Ca2+ pump) blocker. Stimulation of transfected cells with the agonist ATP or IP3 alone (permeabilized cells) also resulted in a significant increase in Ca2+ release from Golgi stores. By immunofluorescence, the IP3 receptor type 1 (IP3R-1) was distributed over the endoplasmic reticulum and codistributed with CALNUC in the Golgi. These results provide direct evidence that CALNUC binds Ca2+ in vivo and together with SERCA and IP3R is involved in establishment of the agonist-mobilizable Golgi Ca2+ store.


1992 ◽  
Vol 126 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Geoffrey R Ambler ◽  
Bernhard H Breier ◽  
Andrzej Surus ◽  
Hugh T Blair ◽  
Stuart N McCutcheon ◽  
...  

We evaluated the interrelationship between, and regulation of, the hepatic growth hormone receptor and serum GH binding protein (GH BP) in pigs treated with recombinant porcine growth hormone (rpGH). Infant and pubertal male pigs (N = 5 per group) received either rpGH 0.15 mg/kg daily or diluent intramuscularly for 12 days. Somatic growth, serum IGF-I and GH BP and [125I]bovine GH (bGH) binding to MgCl2-treated hepatic membrane homogenates were examined. Marked age-related increases were seen in serum GH BP (p<0.001) and [125I]bGH binding to hepatic membranes (p<0.001). GH BP was increased in rpGH treated animals (p = 0.03), from 13.8±1.2 (mean±1 x sem) (controls) to 17.8±2.0% in infants, and from 35.2±2.6 (controls) to 41.8±3.4% in pubertal animals. [125I]bGH binding to hepatic membranes was also increased by rpGH treatment (p<0.05), from 7.0±1.6 (controls) to 15.4±3.6% in infants and from 53.7±7.1 (controls) to 65.1±11.8% in pubertal animals. No significant interaction between age and treatment was seen. Overall, serum GH BP correlated significantly with [125I]bGH membrane capacity (r=0.82, p<0.001), with a correlation of r= 0.83 in the infant animals but no significant correlation in the pubertal animals considered alone (r=0.13). Serum IGF-I correlated significantly with serum GH BP (r=0.93, p<0.001) and [125]bGH membrane binding capacity (r = 0.91, p< 0.001). These observations suggest that serum GH BP levels reflect major changes of hepatic GH receptor status. In addition, the present study demonstrates that the hepatic GH receptor can be induced by GH in the infant pig, despite a developmentally low GH receptor population at this age, suggesting potential efficacy of GH at earlier ages than generally considered.


2020 ◽  
Vol 52 (01) ◽  
pp. 34-34
Author(s):  
Irine Ioramashvili ◽  
Rusudan Sujashvili ◽  
Marika Gamkrelidze ◽  
Sofia Tsitsilashvili

Gastrointestinal cancers (GI) are one of the most abundant types of cancers among the world population, though statistical data indicate that in eastern Asia these types of cancer occur 4 times more often than in Western Europe. Absence of treatment of bacterial infections, obesity, and lack of vegetable food in a diet can be the case of GI cancer. All pathologies are inevitably connected to the changes in cell cycle, abnormal protein amount and their dysfunction. Serum proteins are widely used as an additional source of information about body condition, also changes in protein composition can point out the mechanism of disease development and effectiveness of treatment. In the presented work we studied protein composition of GI cancer patients in different stages of cancer development, after and before chemotherapy and compared these data to protein composition of healthy control group of voluntaries. Treatment of patients was performed according the guidelines appropriate for the GI cancer. Association of the effectiveness of treatment at the different stages of chemotherapeutic courses and changes of protein composition of blood serum has been assessed. Proteins composition was studies by SDS-PAGE electrophoresis and densitometry analysis. Experimentally gained molecular and statistical information exposed the most vulnerable groups of proteins affected by chemotherapeutic agents indicating targets for searching new biomarkers for treatment effectiveness. Research involving human patients performed in accordance with the requirements of the Council of Europe Convention on Human Rights and Biomedicine, Biomedical Research, as well as the UNESCO Declaration of Bioethics and Human Rights.


1989 ◽  
Vol 262 (3) ◽  
pp. 917-922 ◽  
Author(s):  
R K Singh ◽  
B P Sani ◽  
M I Dawson ◽  
Y F Shealy

A biologically active bifunctional retinoid, ethyl 14-carboxyretinoate, has been synthesized and shown to bind cellular retinoic acid (RA)-binding protein (CRABP) via its free carboxy group. We describe herein the synthesis of 14-carboxy-13-cis-retinamide-Sepharose 4B, which is an affinity matrix bearing an all-trans-RA moiety, and thus was used to purify and characterize CRABP from chick-embryo skin. An amide bond was first formed between the free carboxy group of the retinoid and a primary amino group of aminohexyl-Sepharose 4B, by reaction with carbodi-imide, and the ester group of the resin-bound retinoid was then hydrolysed in an alkaline medium. Polyacrylamide-gel electrophoresis and f.p.l.c. Superose column-chromatographic analysis demonstrated that the affinity-purified CRABP (Mr 15,000) was close to electrophoretic homogeneity (greater than 90%) and specifically interacts with RA. By using affinity gel chromatography, conversion of holo-CRABP into apo-CRABP by treatment with p-hydroxymercuribenzoate and a possible involvement of a thiol group in RA binding to CRABP were established. This affinity procedure provides several advantages: (i) 14-carboxy-13-cis-retinamide-Sepharose exhibited high efficiency and selectivity for RA-binding protein (i.e. retinol- or fatty-acid-binding proteins did not bind); (ii) the presence of the amide linkage between the ligand and the matrix makes this affinity resin relatively stable to cytosolic enzymes; and (iii) other RA-binding proteins, e.g. nuclear receptor(s), may be purified.


1961 ◽  
Vol 41 (2) ◽  
pp. 236-252 ◽  
Author(s):  
B. D. Owen ◽  
J. M. Bell ◽  
C. M. Williams ◽  
R. G. Oakes

Five experiments involving 90 newborn colostrum-deprived pigs were conducted in an attempt to develop a method of rearing applicable in a non-isolated environment. Immune globulins, prepared by ammonium sulphate fractionation of porcine serum, and comprised of a mixture of approximately 75 per cent γ-globulin and 25 per cent β-globulin, were administered orally or parenterally in varying amounts and for varying periods of time. In two experiments porcine albumin, in serum or in a semi-purified solution, was provided in addition to the immune globulins. The distribution of serum proteins in the pigs was studied from birth to 12 weeks of age by paper strip electrophoresis.Parenteral administration of immune globulins did not provide an effective passive immunity, nor did oral administration for 1 day post-partum. A marked improvement in survival occurred when oral administration was continued for 5 days, and it was further found that this treatment provided apparently complete protection against infection during the 5-day period of administration. Albumin appeared to further improve survival.These results, together with the relatively poor survival obtained with positive control pigs (nursed 24 hours) suggested a continuing need for a supply of immune globulins in the lumen of the intestinal tract. Presumably these globulins were active as coproantibodies.The percentage survival in pigs weighing 3 pounds or more at birth was substantially higher than in smaller pigs. Mortality in these experiments was usually attributable to colibacillosis.Serum immune globulin levels at 2 days of age in the artificially reared pigs were elevated in proportion to the amount of globulins given. The effect of albumin was to create a serum protein pattern resembling that of suckled pigs. A marked decline in γ-globulin levels from 2 days to approximately 6 weeks was observed.


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