Characterization of the neutral pH-optimum sphingomyelinase from rat brain: Inhibition by copper II and ganglioside GM3

Resident mouse peritoneal macrophages contain a phospholipase C of high activity that is specific for phosphatidylinositol. The activity has a neutral pH optimum, is Ca2+-dependent and has a maximum reaction velocity of 525nmol/h per mg of protein. Certain phenothiazines are potent inhibitors of this activity.

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Soluble neutral maltase–glucoamylase from the small intestine: separation and characterization of components with differing affinity for concanavalin A

Canadian Journal of Biochemistry ◽

10.1139/o82-129 ◽

1982 ◽

Vol 60 (11) ◽

pp. 1007-1013 ◽

Cited By ~ 2

Author(s):

G. Forstner ◽

A. Salvatore ◽

L. Lee ◽

J. Forstner

Keyword(s):

Concanavalin A ◽

Gradient Elution ◽

Soluble Form ◽

Rat Intestine ◽

Ph Optimum ◽

Molecular Weights ◽

Neutral Ph ◽

Membrane Bound ◽

Sepharose 4B

Intestinal maltase with a neutral pH optimum exists in both a brush border membrane-bound form and a soluble form in suckling rat intestine. Previous experiments in our laboratory have shown that the soluble enzyme contains a component which binds much more tightly to concanavalin A (ConA) than solubilized forms of the membrane enzyme. We studied the origin of this component by subjecting neutral, soluble maltase activity to chromatography on Sepharose 4B at age 13, 18 (preweaning), and 25 (postweaning) days. At 13 days, two maltase peaks were obtained with approximate molecular weights of 400 000 (peak I) and 150 000 (peak II). Peak II was less prominent at 18 days and was absent at 25 days. At 13 days, the majority of peak I consisted of material which was bound between 0.025 and 0.05 M α-methyl mannoside on gradient elution chromatography of ConA-Sepharose. Peak II contained material which eluted between 0.075 and 0.3 M α-methyl mannoside. At 25 days, all of the soluble maltase eluted between 0.025 and 0.04 M α-methyl mannoside. Peak I and peak II maltases had similar pH optima and Km's for maltase. Peak II maltase had a fourfold greater activity toward glycogen than peak I maltase with approximately the same activity for palatinose, turanose, and trehalose. Both maltases were precipitated by an antibody raised against adult membrane-bound maltase. Soluble maltase with neutral pH activity in the suckling rat intestine, therefore, consists of two immunologically related isozymes which differ in their molecular weight, their binding by ConA, and their specificity for glycogen. The small isozyme disappears at or about the time of weaning.

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MICROBIAL BETA-GALACTOSIDASE: A SURVEY FOR NEUTRAL pH OPTIMUM ENZYMES

Journal of Milk and Food Technology ◽

10.4315/0022-2747-37.4.199 ◽

1974 ◽

Vol 37 (4) ◽

pp. 199-202 ◽

Cited By ~ 6

Author(s):

L. C. Blankenship ◽

P. A. Wells

Keyword(s):

Ammonium Sulfate ◽

Dairy Products ◽

Skim Milk ◽

Product Inhibition ◽

Ph Optimum ◽

Neutral Ph ◽

Cation Activation ◽

Pure Cultures ◽

Beta Galactosidase

Pure cultures of yeast, molds, and bacteria were screened for neutral pH optimum β-galactosidases (lactases) that would be suitable in dairy products applications. Only 2 of 125 identified and 10 of 250 unidentified cultures warranted further study. These cultures produced high levels of β-galactosidase with moderate galactose product inhibition. Characterization of the partially purified enzymes from unidentified cultures revealed that all required either Na+, K+ or Mg++ cation activation, were inhibited by Cu+ +, Mn+ +, and Fe+ + +, were most active around pH 6.8, and were unstable during storage (at either – 196 C or 4 C) except in the presence of 0.5 m ammonium sulfate. Most of the enzymes compared favorably in performance with a commercially available β-galactosidase when tested in skim milk.

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Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649147 ◽

1974 ◽

Vol 31 (01) ◽

pp. 072-085 ◽

Cited By ~ 5

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.

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