scholarly journals Control of δ-aminolaevulate synthetase activity in Rhodopseudomonas spheroides

1969 ◽  
Vol 111 (4) ◽  
pp. 385-394 ◽  
Author(s):  
J. Marriott ◽  
A. Neuberger ◽  
G. H. Tait
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Synthetase Activity ◽  
Heat Stable ◽  
Cell Extracts ◽  
Spontaneous Activation ◽  
Effect Of Oxygen ◽  
Rhodopseudomonas Spheroides ◽  
No Activation

1. δ-Aminolaevulate synthetase from Rhodopseudomonas spheroides grown semi-anaerobically undergoes a spontaneous activation during the first hour after the disruption of cells when homogenates are stored at 4°. 2. After cultures of R. spheroides growing semi-anaerobically are oxygenated no activation of δ-aminolaevulate synthetase occurs in cell extracts. Cessation of activation in extracts is almost complete 10min. after oxygenation of cells has begun. 3. A heat-stable fraction of low molecular weight from semi-anaerobic cells reactivates δ-aminolaevulate synthetase in extracts of oxygenated cells and appears to contain a compound responsible for the spontaneous activation. 4. A heat-stable fraction of low molecular weight from oxygenated cells inhibits the spontaneous activation in extracts of semi-anaerobic cells. 5. The effect of oxygen on the rate of bacteriochlorophyll synthesis in R. spheroides may be mediated through alterations in the concentrations of a low-molecular-weight activator and inhibitor of δ-aminolaevulate synthetase.

STUDIES ON THE ISOLATION AND NATURE OF THE 'TERREGENS FACTOR'

1954 ◽  
Vol 32 (1) ◽  
pp. 400-406 ◽  
Author(s):  
M. O. Burton ◽  
F. J. Sowden ◽  
A. G. Lochhead
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Ferric Iron ◽  
Test Organism ◽  
The Other ◽  
Inorganic Salts ◽  
Low Molecular Weight ◽  
Straight Chain ◽  
Heat Stable ◽  
Growth Promoting

A procedure is described for the production and concentration of the 'terregens factor' (TF), a bacterial growth promoting substance synthesized by Arthrobacter pascens and essential for the growth of Arthrobacter terregens. From culture filtrates of A. pascens cultivated in a medium of inorganic salts and sucrose, concentrates of TF may be obtained that are active at 0.001 μgm. Per ml., heat stable and contain about 12.7% nitrogen. Acid hydrolysis yielded a number of amino acids, including glutamic acid, glycine, α–alanine, valine, leucine, proline, lysine, and arginine, as well as some unidentified compounds; however, TF does not appear to be a low molecular weight straight chain peptide.Although TF contains no iron, it combines readily with ferrous or ferric iron to form reddish-brown complexes with this metal. Activity for A. terregens is shown by certain iron containing complexes as hemin, coprogen, and ferrichrome. On the other hand none is shown by cytochrome or pulcherrimin; however, aspergillic acid, structurally related to the latter, possesses some growth promoting activity for the test organism.

Trypsin-uncoupled synthesis and secretion of yeast invertase: implications for the mechanism of secretion

1979 ◽  
Vol 25 (4) ◽  
pp. 528-534 ◽  
Author(s):  
Bruce E. Holbein ◽  
Denis K. Kidby
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Subcellular Distribution ◽  
Plasma Membranes ◽  
External Surface ◽  
Internal Surface ◽  
Low Molecular Weight ◽  
Synthetase Activity ◽  
Trypsin Treatment ◽  
Yeast Invertase

The subcellular distribution of invertase was examined after synthesis and secretion by sphaeroplasts had been uncoupled by the addition of 30 μg mL−1 trypsin. Sphaeroplasts secreted only the high molecular weight invertase during uncoupling by trypsin. The level of low molecular weight, 'small' invertase in the soluble internal pool was found to be elevated by over fivefold, and the membrane-associated pool was found to contain low molecular weight invertase in addition to intermediate molecular weight invertase, after 1.5 h of trypsin treatment. Purified plasma membranes from trypsin-treated sphaeroplasts had no detectable mannan synthetase activity. On the basis of these and previous findings, a working hypothesis wherein invertase is synthesized on the internal surface of the plasma membrane and glycosylated during its transit to the external surface is presented.

scholarly journals Glycine decarboxylase in Rhodopseudomonas spheroides and in rat liver mitochondria

1970 ◽  
Vol 118 (5) ◽  
pp. 819-830 ◽  
Author(s):  
G. H. Tait
Keyword(s):  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Low Molecular Weight ◽  
Decarboxylase Activity ◽  
Glycine Decarboxylase ◽  
Heat Stable ◽  
Weight Protein ◽  
Low Molecular Weight Protein ◽  
Rhodopseudomonas Spheroides

1. Glycine decarboxylase and glycine–bicarbonate exchange activities were detected in extracts of Rhodopseudomonas spheroides and in rat liver mitochondria and their properties were studied. 2. The glycine decarboxylase activity from both sources is stimulated when glyoxylate is added to the assay system. 3. Several proteins participate in these reactions and a heat-stable low-molecular-weight protein was purified from both sources. 4. These enzyme activities increase markedly when R. spheroides is grown in the presence of glycine, glyoxylate, glycollate, oxalate or serine. 5. All the enzymes required to catalyse the conversion of glycine into acetyl-CoA via serine and pyruvate were detected in extracts of R. spheroides; of these glycine decarboxylase has the lowest activity. 6. The increase in the activity of glycine decarboxylase on illumination of R. spheroides in a medium containing glycine, and the greater increase when ATP is also present in the medium, probably accounts for the increased incorporation of the methylene carbon atom of glycine into fatty acids found previously under these conditions (Gajdos, Gajdos-Török, Gorchein, Neuberger & Tait, 1968). 7. The results are compared with those obtained by other workers on the glycine decarboxylase and glycine–bicarbonate exchange activities in other systems.

A heat stable low molecular weight inhibitor of lysosomal cysteine proteinases in human serum

1983 ◽  
Vol 110 (2) ◽  
pp. 449-455 ◽  
Author(s):  
Francis Gauthier ◽  
Maurice Pagano ◽  
Frédéric Esnard ◽  
Henri Mouray ◽  
Robert Engler
Keyword(s):  
Molecular Weight ◽  
Human Serum ◽  
Low Molecular Weight ◽  
Cysteine Proteinases ◽  
Heat Stable

An inhibitor of cell cohesion from axenically grown cells of the slime mould, Dictyostelium discoideum

1977 ◽  
Vol 28 (1) ◽  
pp. 107-116
Author(s):  
A.P. Swan ◽  
D.R. Garrod ◽  
D. Morris
Keyword(s):  
Molecular Weight ◽  
Biological Effects ◽  
Low Molecular Weight ◽  
Stationary Phase Culture ◽  
Present Evidence ◽  
Slime Mould ◽  
Heat Stable ◽  
Phase Culture ◽  
Weight Substance ◽  
Millipore Filters

Medium from a stationary phase culture of axenically grown D. discoideum cells contains an inhibitor of cohesion of log phase cells. The inhibitor is a heat-stable, low molecular weight substance. Its biological effects include inhibition of cohesion of aggregation-competent cells, of cells of other slime mould species, the blocking of development on Millipore filters and a reduction in adhesiveness of slime mould cells to glass. Present evidence suggests that the inhibitor may bind to the cell surface.

scholarly journals Control of 5-aminolaevulinate synthetase activity in Rhodopseudomonas spheroides. The purification and properties of an endogenous activator of the enzyme

1973 ◽  
Vol 136 (3) ◽  
pp. 491-499 ◽  
Author(s):  
Albert Neuberger ◽  
John D. Sandy ◽  
George H. Tait
Keyword(s):  
Pyridoxal Phosphate ◽  
Sodium Succinate ◽  
Active Form ◽  
Low Molecular Weight ◽  
Synthetase Activity ◽  
Temperature Dependent ◽  
Endogenous Factors ◽  
Ph Values ◽  
Purification And Properties ◽  
Rhodopseudomonas Spheroides

1. A low-molecular-weight activator of 5-aminolaevulinate synthetase was detected in extracts of Rhodopseudomonas spheroides. The compound activates the enzyme extracted from oxygenated semi-anaerobically grown organisms by a factor of 6–8. 2. The activator was extensively purified, but owing to the exceedingly small amounts that could be extracted in the active form its structure was not determined. 3. The activator contains an acetylatable amino group; it is more stable at acid than at alkaline pH values; it is stable to treatment with I2–KI or potassium ferricyanide, but irreversibly inactivated by Na2S2O4 or NaBH4. 4. The chromatographic, electrophoretic, chemical and stability properties of the activator are similar to those of pteridines; purified activator preparations contain pteridines, as shown by their fluorescence spectrum. This does not, however, constitute an identification of the activator. 5. The activator enhances the activity of crude and partially purified enzyme and does not appear to require other endogenous factors or a supply of air to produce activation. Activation of the purified enzyme, however, requires the presence of either pyridoxal phosphate or sodium succinate. In the absence of both these factors the activator produces a time- and temperature-dependent decay of activity.

AN ANTIBIOTIC PRODUCED BY MICROCOCCUS EPIDERMIDIS

1950 ◽  
Vol 28e (5) ◽  
pp. 212-216 ◽  
Author(s):  
L. J. Loeb ◽  
A. Moyer ◽  
R. G. E. Murray
Keyword(s):  
Molecular Weight ◽  
Streptococcus Pyogenes ◽  
Water Purification ◽  
Active Substance ◽  
Test Organism ◽  
Chemical Data ◽  
Low Molecular Weight ◽  
Heat Stable ◽  
Wide Range ◽  
Physical And Chemical

A stable antibiotic was produced by a strain of Micrococcus epidermidis that showed a wide range of activity against Gram-positive organisms. A mucoid Streptococcus pyogenes was used as test organism. This strain could be made resistant by being grown in increasing concentrations of antibiotic but the organism reverted to its original susceptibility immediately on transfer to medium without antibiotic. There was no antiluminescent activity when tested on Photobacterium fischeri. The test organism was not lysed by the antibiotic. The active substance was dialyzable, was remarkably heat stable, and was soluble only in water or, providing water was present, in solvents that were completely miscible with water. Purification was successful only to the extent of removing a number of inactive fractions by differential solubilities. The activity was destroyed by trypsin but not by pepsin. The physical and chemical data make it probable that the substance is a polypeptide of low molecular weight.

The low molecular weight autoinhibitor of sexual development in Dictyostelium discoideum inhibits cell fusion and zygote differentiation

1984 ◽  
Vol 62 (8) ◽  
pp. 722-731 ◽  
Author(s):  
Stephen P. Szabo ◽  
Danton H. O'Day
Keyword(s):  
Molecular Weight ◽  
Giant Cell ◽  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Cell Formation ◽  
Sexual Cycle ◽  
Low Molecular Weight ◽  
Heat Stable ◽  
Giant Cell Formation ◽  
Zygote Development

A previous study has shown that, during the sexual cycle of Dictyostelium discoideum, zygote giant cell formation is regulated by an autoinhibitor. Experiments reported here show that the autoinhibitor inhibits two events of zygote development: cell fusion and subsequent giant cell differentiation. The autoinhibitor is heat stable and has a molecular weight around 500. Medium containing the autoinhibitor can be diluted 500-fold without loss of activity. Preliminary experiments show that, although levels of ammonia double during the 8-h period of autoinhibitor production, added ammonia does not mimic the inhibiting effect. cAMP at 1 mM inhibits both binucleate formation and differentiation, but the concentration of cyclic AMP in 28-h cultures is only 13.4 pmol, a level which does not affect zygote development. Thus, it is established that neither of these critical regulators of other developmental processes in D. discoideum is the autoinhibitor.

scholarly journals Identification and purification of a liver microsomal glucose 6-phosphatase

1982 ◽  
Vol 205 (3) ◽  
pp. 567-573 ◽  
Author(s):  
A Burchell ◽  
B Burchell
Keyword(s):  
Molecular Weight ◽  
Phosphatase Activity ◽  
Good Yield ◽  
Low Molecular Weight ◽  
Heat Stable ◽  
Heat Treated ◽  
Hepatic Glucose ◽  
Heat Stable Protein

1. Hepatic glucose 6-phosphatase activity was purified 65-fold in good yield over that in cholate-solubilized microsomal fractions. 2. This preparation still contained five major polypeptides and numerous minor contaminants. 3. The smallest of the five major polypeptides (Mr approx. 18 500) could be purified from heat-treated microsomal fractions. 4. Antisera raised against the heat-stable protein doublet was used to immunoprecipitate specifically glucose 6-phosphatase activity from cholate-solubilized microsomal fractions. 5. This work indicates that hepatic microsomal glucose 6-phosphatase appears to be one or both of the low-molecular-weight heat-stable polypeptides.

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