scholarly journals Spatial orientation of glycoproteins in membranes of rat liver rough microsomes. II. Transmembrane disposition and characterization of glycoproteins.

1978 ◽  
Vol 78 (3) ◽  
pp. 894-909 ◽  
Author(s):  
E Rodriguez Boulan ◽  
D D Sabatini ◽  
B N Pereyra ◽  
G Kreibich

Rat liver microsomal glycoproteins were purified by affinity chromatography on concanavalin A Sepharose columns from membrane and content fractions, separated from rough microsomes (RM) treated with low concentrations of deoxycholate (DOC). All periodic acid-Schiff (PAS)-positive glycoproteins of RM showed affinity for concanavalin A Sepharose; even after sodium dodecyl sulfate (SDS) acrylamide gel electrophoresis, most of the microsomal glycoproteins bound [125I]concanavalin A added to the gels, as detected by autoradiography. Two distinct sets of glycoproteins are present in the membrane and content fractions derived from RM. SDS acrylamide gel electrophoresis showed that RM membranes contain 15--20 glycoproteins (15--22% of the total microsomal protein) which range in apparent mol wt from 23,000 to 240,000 daltons. A smaller set of glycoproteins (five to seven polypeptides), with apparent mol wt between 60,000 and 200,000 daltons, was present in the microsomal content fraction. The disposition of the membrane glycoproteins with respect to the membrane plane was determined by selective iodination with the lactoperoxidase (LPO) technique. Intact RM were labeled on their outer face with 131I and, after opening of the vesicles with 0.05% DOC, in both faces with 125I. An analysis of iodination ratios for individual proteins separated electrophoretically showed that in most membrane glycoproteins, tyrosine residues are predominantly exposed on the luminal face of the vesicles, which is the same face on which the carbohydrate moieties are exposed. Several membrane glycoproteins are also exposed on the cytoplasmic surface and therefore have a transmembrane disposition. In this study, ribophorins I and II, two integral membrane proteins (mol wt 65,000 and 63,000) characteristic of RM, were found to be transmembrane glycoproteins. It is suggested that the transmembrane disposition of the ribophorins may be related to their possible role in ribosome binding and in the vectorial transfer of nascent polypeptides into the microsomal lumen.

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.


1986 ◽  
Vol 32 (11) ◽  
pp. 884-888 ◽  
Author(s):  
Lucila Isabel Barberis ◽  
Alberto Jorge Eraso ◽  
Maria Cristina Pàjaro ◽  
Inès Albesa

Two thiol-activated Klebsiella pneumoniae hemolysins were purified from growth media by means of salt precipitation, gel filtration, ion-exchange chromatography, and polyacrylamide gel electrophoresis. The hemolysins peaks coincided with the protein and glycoprotein peaks as determined by chromatography and electrophoresis, The molecular weights, estimated by gel filtration, were 8400 and 19 000; by sodium dodecyl sulphate–polyacrylamide gel electrophoresis, the values were calculated as 15 500 and 27 000. The electrophoretic bands were best detected by the periodic acid–Schiff method. Reduction of the disulfide linkages did not cause the originally larger molecule to break into 8400 and 19 000 hemolysins. However, trypsin treatment cleaved the 19 000 hemolysin into an active moiety, with an electrophoretic migration similar to the 8400 hemolysin. A naturally occurring proteolytic activity was investigated using pepstatin and antipain. When the trypsin inhibitor was added to the system, the hemolytic activity was detected only in the 19 000 hemolysin and the smaller hemolysin was absent.


1976 ◽  
Vol 54 (5) ◽  
pp. 477-480 ◽  
Author(s):  
James W. Gurd ◽  
W. Howard Evans

Following electrophoresis of ovalbumin in sodium dodecyl sulfate (SDS) this glycoprotein bound 125I-labelled concanavalin A (Con A). The reaction was specific and proportional to the amount of glycoprotein present on the gel. This technique was used to study the Con-A-binding glycoproteins of liver cell surfaces. Mouse liver plasma membranes were purified and subfractionated to yield two fractions corresponding to the bile canalicular surface and the surface between adjacent hepatocytes (Evans, W. H. (1970) Biochem. J. 116, 833–842). Both fractions bound 125I-labelled Con A, the former binding two to three times more lectin than the latter. Following SDS gel electrophoresis individual membrane glycoproteins reacted with 125I-labelled Con A. Both membrane subfractions yielded qualitatively similar Con A binding profiles, seven binding proteins being present in each. The results are consistent with a generally uniform distribution of glycoproteins over the hepatocyte surface. The reaction of lectins with glycoproteins following SDS gel electrophoresis should find general application in the study of membrane composition.


1974 ◽  
Vol 60 (3) ◽  
pp. 616-627 ◽  
Author(s):  
Gert Kreibich ◽  
Ann L. Hubbard ◽  
David D. Sabatini

Rat liver rough microsomes were labeled enzymatically with 125I using lactoperoxidase and glucose oxidase. In intact microsomes only proteins exposed on the outside face of the microsomal membrane were iodinated. Low concentrations of detergent (0.049% deoxycholate) were used to allow entrance of the iodination system into the vesicles without disassembling the membranes. This led to iodination of the soluble content proteins and to an increased labeling of the membrane proteins. The distribution of radioactivity in microsomal proteins was analyzed after separation by sodium dodecyl sulfate acrylamide gel electrophoresis. Most membrane proteins were labeled when intact microsomes were iodinated. No major membrane proteins were exclusively labeled in the presence of low detergent concentrations or after complete membrane disassembly. Therefore it is unlikely that there are major membrane proteins, other than glycoproteins, present only on the inner membrane face or completely embedded within the microsomal membrane. Microsomal proteins were also labeled by incubating rough microsomes with [3H]-NaBH4 after reaction with pyridoxal phosphate. Microsomal membranes were permeable to these small molecular weight reagents as shown by the fact that proteins in the vesicular cavity as well as membrane proteins were labeled with this system.


1983 ◽  
Vol 213 (2) ◽  
pp. 437-444 ◽  
Author(s):  
J B Parry ◽  
J C Stewart ◽  
J Heptinstall

Aspergillus fumigatus (Fresenius), IMI 246651, A.T.C.C. 46324, produces two β-glucosidase enzymes, cotton-solubilizing activity, xylanase and endoglucanase enzymes which can be separated by gel-filtration chromatography. The major endoglucanase does not bind to concanavalin A-Sepharose and does not stain with periodic acid/Schiff reagent. It is homogeneous on polyacrylamide isoelectric focusing (pI = 7.1) and has a mol.wt. of 12500 by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The endoglucanase produces glucose and a mixture of oligosaccharides from cellulose; the purified enzyme has a small dextranase activity. It is stable at 50 degrees C and pH 6.


1986 ◽  
Vol 233 (3) ◽  
pp. 827-837 ◽  
Author(s):  
J Roy Chowdhury ◽  
N Roy Chowdhury ◽  
C N Falany ◽  
T R Tephly ◽  
I M Arias

UDP-glucuronosyltransferase (EC 2.4.1.17) activity was solubilized from male Wistar rat liver microsomal fraction in Emulgen 911, and six fractions with the transferase activity were separated by chromatofocusing on PBE 94 (pH 9.4 to 6.0). Fraction I was further separated into Isoforms Ia, Ib and Ic by affinity chromatography on UDP-hexanolamine-Sepharose 4B. UDP-glucuronosyltransferase in Fraction III was further purified by rechromatofocusing (pH 8.7 to 7.5). UDP-glucuronosyltransferases in Fractions IV and V were purified by UDP-hexanolamine-Sepharose chromatography. The transferase isoforms in Fractions II, III, IV and V were finally purified by h.p.l.c. on a TSK G 3000 SW column. Purified UDP-glucuronosyltransferase Isoforms Ia (Mr 51,000), Ib (Mr 52,000), Ic (Mr 56,000), II (Mr 52,000), IV (Mr 53,000) and V (Mr 53,000) revealed single Coomassie Blue-stained bands on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Isoform III enzyme showed two bands of Mr 52,000 and 53,000. Comparison of the amino acid compositions by the method of Cornish-Bowden [(1980) Anal. Biochem. 105, 233-238] suggested that all UDP-glucuronosyltransferase isoforms are structurally related. Reverse-phase h.p.l.c. of tryptic peptides of individual isoforms revealed distinct ‘maps’, indicating differences in primary protein structure. The two bands of Isoform III revealed distinct electrophoretic peptide maps after limited enzymic proteolysis. After reconstitution with phosphatidylcholine liposomes, the purified isoforms exhibited distinct but overlapping substrate specificities. Isoform V was specific for bilirubin glucuronidation, which was not inhibited by other aglycone substrates. Each isoform, except Ia, was identified as a glycoprotein by periodic acid/Schiff staining.


1977 ◽  
Vol 55 (9) ◽  
pp. 958-964 ◽  
Author(s):  
M. P. C. Ip ◽  
R. J. Thibert ◽  
D. E. Schmidt Jr.

Cysteine-glutamate transaminase (cysteine aminotransferase; EC 2.6.1.3) has been purified 149-fold to an apparent homogeneity giving a specific activity of 2.09 IU per milligram of protein with an overall yield of 15%. The isolation procedures involve the preliminary separation of a crude rat liver homogenate which was submitted sequentially to ammonium sulfate fractionation, TEAE-cellulose column chromatography, ultrafiltration, and isoelectrofocusing. The final product was homogenous when examined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS). A minimal molecular weight of 83 500 was determined by Sephadex gel chromatography. The molecular weight as estimated by polyacrylamide gel electrophoresis in the presence of SDS was 84 000. The purified enzyme exhibited a pH optimum at 8.2 with cysteine and α-ketoglutarate as substrates. The enzyme is inactivated slowly when kept frozen and is completely inactivated if left at room temperature for 1 h. The enzyme does not catalyze the transamination of α-methyl-DL-cysteine, which, when present to a final concentration of 10 mM, exhibits a 23.2% inhibition of transamination of 30 mM of cysteine. The mechanism apparently resembles that of aspartate-glutamate transaminase (EC 2.6.1.1) in which the presence of a labile hydrogen on the alpha-carbon in the substrate is one of the strict requirements.


2019 ◽  
Vol 20 (1) ◽  
pp. 38
Author(s):  
Yusrizal Akmal ◽  
Chairun Nisa ◽  
Savitri Novelina

The study aims to reveal the morphology of the male sex accessory glands of the pangolin at macroscopic and microscopic levels. Macroscopic observation included measurement of length and thickness of each accessory gland while microscopic observation, sample of each accessory gland was processed by histology technique with paraffin method and sliced with 3-5 ?m thickness and stained with hematoxylin-eosin (HE) staining for general structural observation, coloration of alcian blue (AB) pH 2.5 and periodic acid Schiff (PAS) to observe the distribution of acid and neutral mucopolysaccharides in each glands. The results showed that the male sex accessory glands of the pangolin consist of vesicular gland and prostate, and bulbourethral gland which were not observed macroscopically. The average length and thickness of vesicular gland were 1.07 cm and 0.41 cm, while the prostate was 1.17 cm and 0.54 cm respectively. All accessory glands were lobulated and separated with a thick connective tissue into lobes and lobules. Acinar cells in the vesicular glands were a serous type, whereas acinar cells in the prostate and bulbourethral gland were the mucous types. Secretion of vesicular gland contains neutral mucopolysaccharide with low concentrations and prostate containing neutral mucopolysaccharide with moderate conJurnal Veteriner Maret 2019 Vol. 20 No. 1 : 38 - 47 pISSN: 1411-8327; eISSN: 2477-5665 DOI: 10.19087/jveteriner.2019.20.1.38 Terakreditasi Nasional, Dirjen Penguatan Riset dan Pengembangan, online pada http://ojs.unud.ac.id/index.php/jvet Kemenristek Dikti RI S.K. No. 36a/E/KPT/201639 centrations, and did not secrete acid mucopolysaccharide. Secretion of bulbourethral glands contains neutral and acidic mucopolysaccharide with strong concentrations. Macroscopically the bulbourethral gland is not observed but has a high carbohydrate which acts as to produce of cement plasma and rinsing urethra from urine.   


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.


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