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.

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.

Possible Mechanisms for the Increase in Alkaline Phosphatase Activity of Lyophilized Control Material

1972 ◽  
Vol 18 (12) ◽  
pp. 1518-1523 ◽  
Author(s):  
Alistair F Smith ◽  
Barbara A Fogg
Keyword(s):  
Molecular Weight ◽  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Temperature Dependent ◽  
Control Material ◽  
Rate Of Increase ◽  
Control Procedures

Abstract The increased alkaline phosphatase (EC 3.1.3.1) activity of reconstituted lyophilized control sera has recently been the focus of considerable interest because of its possible implications for quality-control procedures. We confirm that these reconstituted materials show a temperature-dependent increase in alkaline phosphatase activity, but could show no alteration in activity of fresh sera. The rate of increase in activity was unaffected by dialysis of the reconstituted material, and occurred more rapidly in dilute solutions. Studies with acrylamide gel electrophoresis and Sephadex G-200 gel filtration showed that, immediately after reconstitution, a high-molecular-weight alkaline phosphatase component predominated; during subsequent spontaneous activation this component decreased, and there was a concomitant increase in a low-molecular-weight alkaline phosphatase component. The results obtained when the reconstituted material was extracted with butanol suggest that the observed changes in alkaline phosphatase activity may be attributed to the breakdown of a complex between alkaline phosphatase and lipoprotein.

scholarly journals The effect of streptozotocin-induced diabetes and of insulin supplementation on glycogen metabolism in rat liver

1977 ◽  
Vol 168 (3) ◽  
pp. 541-548 ◽  
Author(s):  
R L Khandelwal ◽  
S M Zinman ◽  
E J Zebrowski
Keyword(s):  
Phosphatase Activity ◽  
Insulin Treatment ◽  
Glycogen Synthase ◽  
Glycogen Metabolism ◽  
Diabetic Rats ◽  
Phosphorylase Kinase ◽  
Metabolizing Enzymes ◽  
Heat Stable ◽  
Heat Stable Protein ◽  
Streptozotocin Induced Diabetes

The effects of streptozotocin-induced diabetes and of insulin supplementation to diabetic rats on glycogen-metabolizing enzymes in liver were determined. The results were compared with those from control animals. The activities of glycogenolytic enzymes, i.e. phosphorylase (both a and b), phosphorylase kinase and protein kinase (in the presence or in the absence of cyclic AMP), were significantly decreased in the diabetic animals. The enzyme activities were restored to control values by insulin therapy. Glycogen synthase (I-form) activity, similarly decreased in the diabetic animals, was also restored to control values after the administration of insulin. The increase in glycogen synthase(I-form) activity after insulin treatment was associated with a concomitant increase in phosphoprotein phosphatase activity. The increase in phosphatase activity was due to (i) a change in the activity of the enzyme itself and (ii) a decrease in a heat stable protein inhibitor of the phosphatase activity.

Reduction of low-molecular- weight acid phosphatase activity in Alzheimer brains

1993 ◽  
Vol 33 (6) ◽  
pp. 616-621 ◽  
Author(s):  
Shun Shimohama ◽  
Sadaki Fujimoto ◽  
Takashi Taniguchi ◽  
Masakuni Kameyama ◽  
Jun Kimura
Keyword(s):  
Molecular Weight ◽  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Low Molecular Weight

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

Axonal microtubules of crayfish and spiny lobster nerve cords are decorated with a heat-stable protein of high molecular weight

1984 ◽  
Vol 71 (1) ◽  
pp. 1-15
Author(s):  
R.H. Warren
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
High Molecular Weight ◽  
Spiny Lobster ◽  
Mammalian Brain ◽  
Heat Stable ◽  
Associated Proteins ◽  
Heat Stable Protein ◽  
Normal Spacing ◽  
Nerve Cords

Axons of crayfish and spiny lobster ventral nerve cords contain large numbers of microtubules that are decorated with fine filaments. These microtubules can be stabilized in permeabilized axons using buffers that contain either polyethylene glycol or glycerol/dimethyl sulphoxide. In the former, the stabilized microtubules retain their filaments and their normal spacing; in the latter, the filaments are stripped off and the bare microtubules collapse onto one another. This observation has been used as the basis for a method of identifying some of the proteins that make up the filaments. Axons are first permeabilized and stabilized in either buffer and then treated with a microtubule-depolymerizing buffer. The axons treated first with polyethylene glycol release tubulin and significant quantities of microtubule-associated proteins (MAPs), while the axons pre-treated with glycerol release tubulin and only traces of associated proteins. One of the proteins released in largest quantity along with tubulin from polyethylene glycol-treated axons is a high molecular weight, heat-stable MAP that co-electrophoreses with MAP-2 from mammalian brain. This same protein co-purifies with tubulin that is obtained from crayfish nerve cords by two cycles of polymerization and depolymerization. It is concluded that this protein is a component of the filaments that decorate the axonal microtubules of the crayfish and spiny lobster.

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.

Chemical analysis of flavour volatiles in heat-treated milks

1978 ◽  
Vol 45 (3) ◽  
pp. 391-403 ◽  
Author(s):  
Haytham A. Jaddou ◽  
John A. Pavey ◽  
Donald J. Manning
Keyword(s):  
Mass Spectrometry ◽  
Heat Treatment ◽  
Molecular Weight ◽  
Gas Chromatography ◽  
Chemical Composition ◽  
Volatile Compounds ◽  
Raw Milk ◽  
Low Molecular Weight ◽  
Total Volatile ◽  
Heat Treated

SummaryThe effect of heat treatment of milk on low molecular weight, volatile compounds was studied in order to relate changes in the flavour of milks to changes in chemical composition. Milks were heat treated in a UHT plant for 3 or 90 s at 140 °C and stored at ambient temperature for periods up to 112 d. Volatile compounds in raw milk and in heated milks were isolated by a low temperature spray distillation technique and identified using gas chromatography and mass spectrometry. Cabbagey defects in heated milks are correlated with total volatile sulphur and it is concluded that the compounds H2S, COS, CH3SH, CS2 and (CH3)2S could be responsible for this defect.

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