The hydrolysis of wheaten hay hemicellulose by a purified enzyme from rumen microorganisms.

1961 ◽  
Vol 12 (4) ◽  
pp. 651 ◽  
Author(s):  
DJ Walker ◽  
MF Hopgood
Keyword(s):  
Enzyme Activity ◽  
Rumen Microorganisms ◽  
Enzyme Preparations ◽  
Partial Inhibition ◽  
Rumen Microflora ◽  
Sheep Rumen ◽  
Hydrolysis Of

An enzyme hydrolyzing a largely insoluble preparation of hemicellulose from wheaten hay was purified from sheep rumen microflora. The enzyme catalysed the hydrolysis of hemicellulose to xylose, xylobiose, xylotriose, and higher oligosaccharides together with glucose and arabinose. Enzyme activity was rapidly destroyed by heating at temperatures above 40� and by raising the pH above the optimum of 6.0. Purified enzyme preparations did not hydrolyse starch or cellulose. A partial inhibition of hemicellulase activity was observed in the presence of p-chloromercuribenzoate.

scholarly journals Hydrolysis of Plant Mannans by Rumen Protozoal Enzvmes

1969 ◽  
Vol 22 (1) ◽  
pp. 267 ◽  
Author(s):  
RW Bailey ◽  
Blanche DE Gaillard
Keyword(s):  
Trifolium Pratense ◽  
Red Clover ◽  
Rumen Microorganisms ◽  
Polysaccharide Fraction ◽  
Minor Constituents ◽  
Rumen Microflora ◽  
Pasture Plant ◽  
Hydrolysis Of ◽  
Pasture Legume

Mannans or heteromannans (gluco-or galactoglucomannans) are commonly considered to be present in plants only in wood or associated with seeds. The present authors (Gaillard and Bailey 1968) have, however, recently isolated from the leaves and stems of red clover (Trifolium pratense) a polysaccharide fraction giving on hydrolysis galactose, glucose, mannose, and xylose (approximate ratios 1: 4�0: 2�0: 1�3), and which may, therefore, contain a mannan or heteromannan. This polysaccharide is designated "clover mannan" in the present work. Although apparently absent from grasses, such mannans may be common as minor constituents of pasture legume leaves and stems; for example, 1-2% of polymer mannose was reported present in lucerne (Hirst, MacKenzie, and Wylam 1959). Ivory nut (Phytelephas macrocarpa) mannan has been reported to be digested by ruminants (Beals and Lindsey 1916) and these pasture-plant mannans are probably also digested, presumably after hydrolysis by mannanases secreted by the rumen microflora. The only study of the action of rumen microorganisms on plant mannans appears to be that of Williams and Doetsch (1960), who isolated from the rumens of cows fed guaran (soluble galactomannan) several bacteria which could grow on this poly-saccharide and which secreted extracellular mannanase.

Macrophage Inhibition of Collagen-Induced Platelet Aggregation

1979 ◽  
Vol 42 (04) ◽  
pp. 1207-1216 ◽  
Author(s):  
Berit Mørland
Keyword(s):  
Enzyme Activity ◽  
Platelet Aggregation ◽  
Peritoneal Macrophage ◽  
Cultured Cells ◽  
Culture Media ◽  
Human Platelets ◽  
Mouse Peritoneal Macrophage ◽  
Collagenase Activity ◽  
Partial Inhibition ◽  
Macrophage Phagocytosis

SummaryCollagen was incubated with cells or media fractions of mouse peritoneal macrophage cultures, and its aggregating effect on human platelets was tested. Incubation with lysates of cultured cells completely abolished the normal collagen-induced platelet aggregation, while incubation with media fractions only caused partial inhibition. The latter inhibition was more pronounced after macrophage phagocytosis of latex particles, while endocytosis of endotoxin had no effect.Corresponding macrophage cultures were also tested for specific collagenase activity, using 14C-glycine labelled collagen as substrate. Collagenase activity was found in the culture media fractions only, and the enzyme activity could be enhanced by endocytosis of latex as well as endotoxin.It appears that the effect of macrophage lysates and media on collagen-platelet interaction cannot be ascribed only to secretion of collagenase from macrophages.

THE HYDROLYSIS OF MONOPHOSPHOINOSITIDE BY EXTRACTS OF BRAIN

1967 ◽  
Vol 45 (6) ◽  
pp. 853-861 ◽  
Author(s):  
W. Thompson
Keyword(s):  
Fatty Acids ◽  
Enzyme Activity ◽  
Calcium Ions ◽  
Brain Extract ◽  
Monovalent Cations ◽  
High Concentration ◽  
Diffusible Factor ◽  
Hydrolysis Of ◽  
The Brain ◽  
Long Chain

The hydrolysis of monophosphoinositide by soluble extracts from rat brain is described. Diglyceride and inositol monophosphate are liberated along with a small amount of free fatty acids. Hydrolysis of the lipid is optimal at pH 5.4 in acetate buffer. The reaction is stimulated by calcium ions or by high concentration of monovalent cations and, to a less extent, by long-chain cationic amphipathic compounds. Enzyme activity is lost on dialysis of the brain extract and can be restored by diffusible factor(s). Some differences in the conditions for hydrolysis of mono- and tri-phosphoinositides are noted.

scholarly journals Pre-fermentative treatment of a model wine with aim to serve as a functional food with decreased alcohol content

2017 ◽  
Vol 63 (01) ◽  
pp. 47-53
Author(s):  
Irina Mladenoska ◽  
Verica Petkova ◽  
Tatjana Kadifkova Panovska
Keyword(s):  
Enzyme Activity ◽  
Gluconic Acid ◽  
Functional Food ◽  
Ph Value ◽  
Enzymatic Reaction ◽  
Alginate Beads ◽  
High Concentration ◽  
Ph Optimum ◽  
Enzyme Preparations ◽  
Initial Ph

The effect of substrate concentration on the enzyme activity in the reaction of glucose conversion into gluconic acid was investigated by using three different enzyme preparations in media with two different glucose concentrations. The media were simulating the conditions in the must, thus named as minimal model must, and were composed form combination of several organic acids and glucose. Those media were having initial pH of 3.5 that is a very unfavorable for glucose oxidase activity having a pH optimum at the pH value of 5.5. Among the three preparations used, the bakery additive, Alphamalt Gloxy 5080, was the most active in the medium with glucose concentration of 10 g/L, showing conversion of more than 70% for the period of 24 h, while the same enzyme preparation in the medium with 100 g/L glucose converted only about 7% of glucose. The pH value of the medium at the beginning and at the end of the enzymatic reaction was a good indicator of the enzyme activity. It seems that for the conversion of glucose in higher concentration, enzymatic preparation in high concentration should also be used. The preliminary attempt of immobilization of two preparations of glucose oxidases in alginate beads was also performed and a successful immobilization procedure for utilization in food industry was preliminarily developed. Keywords: glucose oxidases, enzymatic pretreatment, glucose, gluconic acid, model wine, functional food

scholarly journals Application of β-glucosidase Immobilized on Chitosan microspheres in Degradation of Polydatin in Polygonum cuspidatum

2021 ◽  
Vol 233 ◽  
pp. 02034
Author(s):  
Wei Zong ◽  
Shan Liu ◽  
Jeonyun Yun ◽  
Xiong Xiao ◽  
Zujun Deng ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Cost Reduction ◽  
Degradation Rate ◽  
Temperature Stability ◽  
Catalytic Efficiency ◽  
Efficient Production ◽  
Polygonum Cuspidatum ◽  
Optimum Temperature ◽  
Preparation Conditions ◽  
Hydrolysis Of

Resveratrol in Polygonum cuspidatum is a β-glycoside, which can be hydrolyzed to resveratrol by β-glucosidase. it is an efficient production process to degrade polydatin from Polygonum cuspidatum extract by immobilized β-glucosidase. It is of great significance to explore suitable immobilization conditions to improve the catalytic efficiency and reusability of β-glucosidase for polydatin degradation and cost reduction. In this paper, the recombinant Escherichia coli bgl2238, which was screened and constructed from corn soil of Heilongjiang Province in the early laboratory, was immobilized by chitosan adsorption and glutaraldehyde crosslinking. The preparation conditions and immobilization process of bgl2238 were determined by single factor method: the optimal crosslinking time was 1 h, the optimal crosslinking temperature was 20 °C, the recovery rate of enzyme activity of bgl2238 was 87 %, and the enzyme activity was 859.65 mU/g. The optimum temperature of the immobilized bgl2238 is 50 °C, which is 6 °C higher than that of the free bgl2238, and the temperature stability and pH stability are improved. After six consecutive hydrolysis of Polygonum cuspidatum, the degradation rate of polydatin is still over 70 %, which proves that the immobilized bgl2238 has good reusability. This will be helpful to evaluate the application prospect of β - glucosidase immobilized in this system and determine the best conditions for its production.

THE METABOLISM OF THE ERYTHROCYTE: X. THE INORGANIC PYROPHOSPHATASE OF THE ERYTHROCYTE

1956 ◽  
Vol 34 (1) ◽  
pp. 121-129 ◽  
Author(s):  
A. Malkin ◽  
O. F. Denstedt
Keyword(s):  
Enzyme Activity ◽  
Calcium Ions ◽  
Human Erythrocyte ◽  
Inorganic Pyrophosphatase ◽  
Magnesium Ions ◽  
Constant Ratio ◽  
Inorganic Pyrophosphate ◽  
Noncompetitive Inhibitor ◽  
Pyrophosphatase Activity ◽  
Hydrolysis Of

The activity of the pyrophosphatase which catalyzes the hydrolysis of inorganic pyrophosphate in the erythrocyte of the human, the rabbit, and the chicken is confined entirely to the cytoplasm of the cell. Following preincubation, the enzyme activity in the human erythrocyte is diminished, but pre-incubation in the presence of cysteine or glutathione prevents the diminution of the enzyme activity. Aging of the hemolyzate of the human erythrocytes results in a marked loss of the inorganic pyrophosphatase activity. The diminished activity can be restored by the addition of cysteine or glutathione to the reaction mixture; but after the hemolyzate has aged for five or six days at 5 °C, the loss in the enzyme activity can no longer be restored with these reagents. Fluoride and calcium ions inhibit the activity of the enzyme, while magnesium ions are essential for its activity. Calcium is a noncompetitive inhibitor, while the inhibition by fluoride is of a "quadratic" nature. If a constant ratio of magnesium to pyrophosphate is maintained, the quadratic inhibition can be converted to the "uncompetitive" type of inhibition.

SOME ASPECTS OF THE ENZYMIC HYDROLYSIS OF URINARY 17-KETOSTEROID CONJUGATES

1960 ◽  
Vol 38 (1) ◽  
pp. 769-776
Author(s):  
R. Hobkirk ◽  
J. J. Cohen
Keyword(s):  
Liver Enzymes ◽  
Striking Difference ◽  
Degree Of Hydrolysis ◽  
Enzyme Preparations ◽  
Bacterial Preparation ◽  
Bacterial Enzyme ◽  
The Difference ◽  
Normal Urine ◽  
High Degree ◽  
Hydrolysis Of

Four enzyme preparations containing β-glucuronidase, of bacterial, mammalian, and molluscan origin, have been shown to be equally effective in liberating 17-ketosteroids (17-KS) of the 5β-(etiocholane) configuration in normal urine. The bacterial preparation releases steroids of the 5α-(androstane) configuration more rapidly than do the molluscan enzymes and with much greater ease than does the liver enzyme. In view of the data obtained it seems unlikely that the striking difference between the bacterial and liver enzymes can be due to the hydrolysis of some labile conjugate, such as sulphate, by the former and not by the latter. Possibilities that the difference is due to the hydrolysis of an unknown type of urinary conjugate by the bacterial preparation, or to the low specificity of the bacterial β-glucuronidase, are discussed. The high degree of hydrolysis of 17-KS conjugates by the bacterial enzyme followed by solvolysis suggests this as a most useful hydrolytic procedure.

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