scholarly journals Characterization of ornithine decarboxylase of tobacco cells and tomato ovaries.

1982 ◽  
Vol 201 (2) ◽  
pp. 373-376 ◽  
Author(s):  
Y M Heimer ◽  
Y Mizrahi
Keyword(s):  
Molecular Weight ◽  
Ornithine Decarboxylase ◽  
Pyridoxal Phosphate ◽  
Apparent Molecular Weight ◽  
Ph Optimum ◽  
Tobacco Cells ◽  
Thiol Reagent ◽  
Mammalian Origin

Some characteristics of L-ornithine decarboxylase of tomato ovaries and tobacco cells are described. The enzyme has a pH optimum of 8.0. It requires pyridoxal phosphate and thiol reagent (dithiothreitol) for activity. It is specific for L-ornithine and has an apparent Km of 1.4 × 10-4 M. It has an apparent molecular weight of 107000. Putrescine inhibited the activity in vitro. Spermidine and spermine also inhibit the enzyme, but less effectively. It is concluded that the enzyme is similar to that of mammalian origin and likewise fulfils a function related to cell proliferation.

scholarly journals Characterization of the purified Chlamydomonas minus agglutinin.

1985 ◽  
Vol 101 (3) ◽  
pp. 1144-1152 ◽  
Author(s):  
P Collin-Osdoby ◽  
W S Adair
Keyword(s):  
Molecular Weight ◽  
Apparent Molecular Weight ◽  
Agarose Beads ◽  
Sds Page ◽  
Sexual Agglutinins ◽  
Molecular Morphology ◽  
High Degree

Chlamydomonas flagellar sexual agglutinins are responsible for the adhesion of opposite mating-type (plus and minus) gametes during the first stages of mating. Purification and partial characterization of the plus agglutinin was previously reported (Adair, W. S., C. J. Hwang, and U. W. Goodenough, 1983, Cell, 33:183-193). Here we characterize the purified minus molecule. We show it to be a high molecular weight, hydroxyproline-rich glycoprotein that migrates in the 3% stacking region of an SDS-polyacrylamide gel and is absent from two nonagglutinating minus mutants. Plus and minus agglutinins are remarkably similar, although nonidentical, in amino acid composition, molecular morphology, and reactivity in vivo and in vitro with monoclonal antibodies raised against the plus agglutinin. Moreover, the adhesiveness of both plus and minus agglutinins, when coupled to agarose beads, is abolished by thermolysin, trypsin, periodate, alkaline borohydride, reducing agents, or heat, but unaffected by exo- or endoglycosidases. The minus agglutinin, however, migrates just ahead of the plus molecule on SDS PAGE, is excluded from an anion-exchange (Mono Q) column, elutes earlier during hydrophobic interaction (Bio-gel TSK Phenyl 5PW) chromatography, and is sensitive to chymotrypsin digestion (unlike the plus agglutinin); therefore, it differs from the plus agglutinin in apparent molecular weight, net charge, relative hydrophobicity and proteolytic susceptibility. Nevertheless, our results generally demonstrate a high degree of homology between these complementary cell-cell recognition/adhesion molecules, which suggests that they are specified by genes that have a common evolutionary origin.

scholarly journals Purification of a high-molecular-weight somatoliberin (growth-hormone-releasing factor) from pig hypothalami

1983 ◽  
Vol 209 (3) ◽  
pp. 643-651 ◽  
Author(s):  
J E C Sykes ◽  
P J Lowry
Keyword(s):  
Molecular Weight ◽  
Growth Hormone ◽  
Amino Acid ◽  
Response Curve ◽  
Gel Filtration ◽  
Apparent Molecular Weight ◽  
Amino Acid Residues ◽  
Growth Hormone Releasing Factor

Preliminary observations [Sykes & Lowry (1980) J. Endocrinol. 85, 42P-43P] had suggested that the major hypothalamic somatoliberin (growth-hormone-releasing factor) was a larger peptide than the other characterized hypothalamic factors, with an elution position on Sephadex G-50 between those of neurophysin and corticotropin. The present paper reports the isolation and preliminary characterization of pig hypothalamic somatoliberin. Acid extracts of pig stalk median eminence were purified by gel filtration and preparative and analytical high-pressure liquid chromatography to yield a preparation that was specific in the release of somatotropin (growth hormone) in vitro, giving a steep dose-response curve at doses in the range 0.20-3.0 ng. Amino acid analysis revealed a non-cysteine-containing peptide with a high number of glutamate (or glutamine) and aspartate (or asparagine) residues. The peptide had about 56-57 amino acid residues and an apparent molecular weight of 6400, in keeping with its elution position on a column of Sephadex G-50.

Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
Author(s):  
M Kopitar ◽  
M Stegnar ◽  
B Accetto ◽  
D Lebez
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Gel Electrophoresis ◽  
Gel Filtration ◽  
Ph Optimum ◽  
Isolation And Characterization ◽  
Ph Range ◽  
Inhibition Studies ◽  
Final Purification

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.

Partial characterization of cheese-ripening proteinases produced by the yeastKluyveromyces lactis

1983 ◽  
Vol 50 (4) ◽  
pp. 469-480 ◽  
Author(s):  
Paul A. Grieve ◽  
Barry J. Kitchen ◽  
John R. Dulley ◽  
John Bartley
Keyword(s):  
Molecular Weight ◽  
Kluyveromyces Lactis ◽  
Apparent Molecular Weight ◽  
Aminopeptidase Activity ◽  
Carboxypeptidase Y ◽  
Casein Hydrolysis ◽  
Cheese Ripening ◽  
Caseinolytic Activity ◽  
Proteinase A

SUMMARYAn extract ofKluyveromyces lactis416 and a β-galactosidase preparation (Maxilact 40000) contaminated with proteinase, showed similar pH profiles of caseinolytic activity. Similar modes of casein hydrolysis (κ-, > αs-, ≥ β-) were observed at pH 5·0 (the pH of Cheddar cheese), without detection of bitterness. The contaminated Maxilact preparation contained similar proteinase types to those detected in an autolysate ofK. lactis. Both the autolysate and the Maxilact preparation contained acid endopeptidase (proteinase A), serine endopeptidase (proteinase B) and serine exopeptidase (carboxypeptidase Y) activities. Some aminopeptidase activity was also detected in both preparations. There were some differences in apparent molecular weight and charge properties between proteinase A and B and carboxypeptidase Y from the 2 proteinase sources.

Processing of the precursor to a chloroplast ribosomal protein made in the cytosol occurs in two steps, one of which depends on a protein made in the chloroplast

1985 ◽  
Vol 5 (5) ◽  
pp. 1093-1099
Author(s):  
R J Schmidt ◽  
N W Gillham ◽  
J E Boynton
Keyword(s):  
Molecular Weight ◽  
Protein Synthesis ◽  
Ribosomal Protein ◽  
Apparent Molecular Weight ◽  
Protein L ◽  
Mature Form ◽  
Chloroplast Protein Synthesis ◽  
Made In

In pulse-chase experiments in which log-phase cells of Chlamydomonas reinhardtii were labeled in vivo for 5 min with H2(35)SO4, fluorographs of immunoprecipitates from whole cell extracts revealed that chloroplast ribosomal proteins L-2, L-6, L-21, and L-29, which are made in the cytosol and imported, appeared in their mature forms. However, in the case of chloroplast ribosomal protein L-18, which is also made in the cytoplasm and imported, a prominent precursor with an apparent molecular weight of 17,000 was found at the end of a 5-min pulse. This precursor was processed to its mature size (apparent molecular weight of 15,500) within the first 5 min of the subsequent chase. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the precursor to L-18 formed in vivo was 1.5 kilodaltons smaller than the primary product detected in translations of Chlamydomonas polyadenylated RNA in vitro. Upon a 10-min incubation with a postribosomal supernatant from Chlamydomonas, the 18,500-dalton precursor detected in vitro could be partially converted into a polypeptide that comigrated with the 17,000-dalton precursor detected in extracts of cells labeled in vivo. Under conditions in which the total amounts of chloroplast proteins had been reduced and cells were made to synthesize ribosomes rapidly, the apparent half-life of the 17,000-dalton precursor was extended over that seen in log-phase cells. When chloroplast protein synthesis was inhibited with lincomycin for 3 h before labeling under these conditions, the 17,000-dalton L-18 precursor but not the mature form was found, and the precursor was slowly degraded during a 60-min chase. When cells were placed in the dark for 3 h before labeling, processing of this precursor to the mature form appeared unaffected, but the chloroplast-synthesized ribosomal protein L-26 was detected, indicating that chloroplast protein synthesis was still occurring. We interpret these results to indicate that the maturation of protein L-18 in vivo involves at least two processing steps, one of which depends on a protein made on chloroplast ribosomes.

scholarly journals Role of pyridoxal phosphate in mammalian polyamine biosynthesis. Lack of requirement for mammalian S-adenosylmethionine decarboxylase activity

1977 ◽  
Vol 166 (1) ◽  
pp. 81-88 ◽  
Author(s):  
A E Pegg
Keyword(s):  
Ornithine Decarboxylase ◽  
Pyridoxal Phosphate ◽  
Vitamin B ◽  
Decarboxylase Activity ◽  
Deficient Diet ◽  
Polyamine Biosynthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Ornithine Decarboxylase Activity

1. Polyamine concentrations were decreased in rats fed on a diet deficient in vitamin B-6. 2. Ornithine decarboxylase activity was decreased by vitamin B-6 deficiency when assayed in tissue extracts without addition of pyridoxal phosphate, but was greater than in control extracts when pyridoxal phosphate was present in saturating amounts. 3. In contrast, the activity of S-adenosylmethionine decarboxylase was not enhanced by pyridoxal phosphate addition even when dialysed extracts were prepared from tissues of young rats suckled by mothers fed on the vitamin B-6-deficient diet. 4. S-Adenosylmethionine decarboxylase activities were increased by administration of methylglyoxal bis(guanylhydrazone) (1,1′-[(methylethanediylidine)dinitrilo]diguanidine) to similar extents in both control and vitamin B-6-deficient animals. 5. The spectrum of highly purified liver S-adenosylmethionine decarboxylase did not indicate the presence of pyridoxal phosphate. After inactivation of the enzyme by reaction with NaB3H4, radioactivity was incorporated into the enzyme, but was not present as a reduced derivative of pyridoxal phosphate. 6. It is concluded that the decreased concentrations of polyamines in rats fed on a diet containing vitamin B-6 may be due to decreased activity or ornithine decarboxylase or may be caused by an unknown mechanism responding to growth retardation produced by the vitamin deficiency. In either case, measurements of S-adenosylmethionine decarboxylase and ornithine decarboxylase activity under optimum conditions in vitro do not correlate with the polyamine concentrations in vivo.

An integral membrane protein antigen associated with the membrane attachment sites of actin microfilaments is identified as an integrin beta-chain

1988 ◽  
Vol 8 (2) ◽  
pp. 564-570
Author(s):  
P A Maher ◽  
S J Singer
Keyword(s):  
Molecular Weight ◽  
Membrane Protein ◽  
Protein Complex ◽  
Apparent Molecular Weight ◽  
Integral Membrane Protein ◽  
Beta Chain ◽  
Attachment Sites ◽  
Wide Range ◽  
Membrane Attachment

A monoclonal antibody (MAb 30B6) was recently described by Rogalski and Singer (J. Cell Biol. 101:785-801, 1985) which identified an integral membrane glycoprotein of chicken cells that was associated with a wide variety of sites of actin microfilament attachments to membranes. In this report, we present a further characterization of this integral protein. An immunochemical comparison was made of MAb 30B6 binding properties with those of two other MAbs, JG9 and JG22, which identify a component of a membrane protein complex that interacts with extracellular matrix proteins including fibronectin. We showed that the 110-kilodalton protein recognized by MAb 30B6 in extracts of chicken gizzard smooth muscle is identical, or closely related, to the protein that reacts with MAbs JG9 and JG22. These 110-kilodalton proteins are also structurally closely similar, if not identical, to one another as demonstrated by 125I-tryptic peptide maps. However, competition experiments showed that MAb 30B6 recognizes a different epitope from those recognized by MAbs JG9 and JG22. In addition, the 30B6 antigen is part of a complex that can be isolated on fibronectin columns. These results together establish that the 30B6 antigen is the same as, or closely similar to, the beta-chain of the protein complex named integrin, which is the complex on chicken fibroblast membranes that binds fibronectin. Although the 30B6 antigen is present in a wide range of tissues, its apparent molecular weight on gels varies in different tissues. These differences in apparent molecular weight are due, in large part, to differences in glycosylation.

Characterization Of The ADP-Induced Fibrinogen Btnd1Ng Sites On Human Platelets Using Photoaffinity Techniques: Some Preliminary Findings

1981 ◽  
Author(s):  
Ellinor I Peerschke ◽  
Mariorie B Zucker ◽  
Avner Rotman
Keyword(s):  
Molecular Weight ◽  
Apparent Molecular Weight ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Membrane Fragment ◽  
Fibrinogen Receptor ◽  
Congenital Deficiency ◽  
Sds Page ◽  
Platelet Membrane Receptor

The interaction of fibrinogen with its, platelet membrane receptor was investigated using 125-labeled fibrinogen which was photoaffinity labeled with a light-sensitive azide. This photoreactive material (125I-NPA-fibr) was indistinguishable from unlabeled fibrinogen as well as from iodinated fibrinogen on SDS-PAGE. It bound specifically to platelets stimulated with ADP and was crosslinked to the platelet membrane after exposure to light ( λ >300 nm) for 4 min. No crosslinking was observed in the presence of EDTA or with platelets that failed to aggregate with ADP either due to the congenital deficiency thrombasthenia or following incubation with EDTA for 8 min at 37° , pH 7.8 and recalcification. SDS-PAGE of platelets bearing crosslinked 125I-NPA-fibr revealed a radiolabeled band of about 450,000 daltons in addition to the 340,000 dalton radioactive band of fibrinogen, suggesting that fibrinogen had been covalently bound to a platelet membrane component with an intact apparent molecular weight of approximately 110,000 daltons. Following reduction, an extra radioactive band was noted at 80,000 daltons. As the A∝-chains of fibrinogen were too weakly labeled to be detected by autoradiography, this indicated that either the Bβ or γchain of fibrinogen was attached to a 25,000-35,000 molecular weight platelet membrane fragment. We conclude that the additional radioactive bands observed after electrophoresis of platelets bearing specifically bound-photoaffinity labeled 125I-fibrinogen most likely represent the binding of the B β or γ chains of fibrinogen to the platelet fibrinogen receptor which may be GPIIb.

Localization and Functional Characterization of Three Thylakoid Membrane Polypeptides of the Molecular Weight 66000

1977 ◽  
Vol 32 (9-10) ◽  
pp. 817-827 ◽  
Author(s):  
Friederike Koenig ◽  
Wilhelm Menke ◽  
Alfons Radunz ◽  
Georg H. Schmid
Keyword(s):  
Molecular Weight ◽  
Electron Transport ◽  
Outer Surface ◽  
Thylakoid Membrane ◽  
Functional Characterization ◽  
Apparent Molecular Weight ◽  
Photochemical Reactions ◽  
Antigenic Determinants ◽  
Reaction Centre

Abstract Three polypeptide fractions with the apparent molecular weight 66 000 were isolated from stroma-freed Antirrhinum chloroplasts which were solubilized with dodecyl sulfate. Antisera to these fractions affect electron transport in distinctly different ways. For the characterization of the three antisera photochemical reactions of chloroplast preparations with artificial electron donors and acceptors as well the analysis of fluorescence rise curves were used. Antiserum 66 000 PSI-96 inhibits electron transport apparently on the acceptor side of photosystem I, provided the antibodies are adsorbed onto the outer surface of the thylakoid membrane. Antiserum 66 000 PSI-88 probably acts directly on the reaction centre I or on its immediate vicinity, if the antibodies are adsorbed at the inner surface of the thylakoid membrane. Antiserum 66 000 PSII-42 inhibits electron trans­ port in the region of photosystem II. The antigen towards which the antiserum is directed appears to belong to the reaction centre II, as also in the condition of high inhibition degrees, the fluorescence intensity remains unchanged. The antigenic determinants are located at the outer surface of the thylakoid membrane.

Isolation and Purification to Apparent Homogeneity of 4,5-Dioxovalerate Aminotransferase from Scenedesmus obliquus Mutant C-2 A′

1988 ◽  
Vol 43 (7-8) ◽  
pp. 563-571 ◽  
Author(s):  
A. Kah ◽  
D. Dörnemann ◽  
H. Senger
Keyword(s):  
Molecular Weight ◽  
Green Alga ◽  
Isoelectric Point ◽  
Pyridoxal Phosphate ◽  
Scenedesmus Obliquus ◽  
Ph Optimum ◽  
Isolation And Purification ◽  
Apparent Homogeneity ◽  
Unicellular Green Alga ◽  
Glyoxylate Aminotransferase

In the present paper the purification of a specific 4,5-dioxovalerate transaminase from pigment mutant C-2 A′ of the unicellular green alga Scenedesmus obliquus to apparent homogeneity is described. The newly isolated enzyme ʟ-glutamate: 4,5-dioxovalerate aminotransferase is not identical with ʟ-alanine: 4,5-dioxovalerate aminotransferase (EC 2.6.1.43) and ʟ-alanine: glyoxylate aminotransferase (EC 2.6.1.44). A procedure for the purification is described and the resulting homogeneous protein is characterized by its Kᴍ-values for oxo-substrates and amino donors, its pyridoxal phosphate requirement, reversability of the catalysis, pH-optimum, isoelectric point and its molecular weight.

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