Dephosphorylation of bovine casein by milk alkaline phosphatase

1976 ◽  
Vol 43 (1) ◽  
pp. 19-26 ◽  
Author(s):  
D. Lorient ◽  
G. Linden
Keyword(s):  
Alkaline Phosphatase ◽  
Ph Value ◽  
Whey Proteins ◽  
Inhibitory Effect ◽  
Optimum Conditions ◽  
Optimum Activity ◽  
Phosphate Ions ◽  
Micellar Casein ◽  
Optimum Ph ◽  
Β Lactoglobulin

SummaryThe pH of optimum activity of alkaline phosphatase from cow's milk depended on the substrate, being 10·1 for p-nitrophenylphosphate, 8·6 for phosphoserine, 8·0 for phosvitin and 6·8 for casein. Individual casein components were dephosphorylated more rapidly than mixtures of αs- and β-caseins or of αs-, β- and κ-caseins and micellar casein. Mixtures of 2 components involving κ-casein were more readily dephosphorylated than αs- and β-casein mixtures. At pH 6·8, lactose, whey proteins and phosphate ions had an inhibitory effect. β-Lactoglobulin had an inhibitory effect only when the pH of the reaction was lower than the optimum pH value of the enzyme. Mg2+ and Zn2+ were not inhibitory. The optimum conditions for dephosphorylation of casein are described.

Potassium iodate-induced proteolysis in ultra heat treated milk during storage: the role of β-lactoglobulin and plasmin

1986 ◽  
Vol 53 (4) ◽  
pp. 601-613 ◽  
Author(s):  
Mary B. Grufferty ◽  
Patrick F. Fox
Keyword(s):  
Whey Proteins ◽  
Inhibitory Effect ◽  
Casein Micelle ◽  
Ph Optimum ◽  
Heat Treated ◽  
Sh Group ◽  
90 C 30 ◽  
C 30 ◽  
Subsequent Storage ◽  
Β Lactoglobulin

SummaryThe report that addition of KI03 (0·1 mm) to milk before ultra high temperature (UHT) treatment induces extensive proteolysis during subsequent storage at 37 °C was confirmed. None was produced by addition of H202 KMn04 or K2Cr207. The pH optimum for KI03-induced proteolysis was between 7·0 and 8·0 and the temperature optimum 37—45 °C. β-Casein was particularly susceptible and the proteolysis pattern was similar to that caused by indigenous alkaline milk proteinase (MPA, plasmin). Addition of plasmin to milk before UHT treatment (140 °C/10 s) caused slight proteolysis during subsequent storage but addition of 0·1 mm-KI03 and plasmin caused extensive proteolysis which was prevented by addition of soyabean trypsin inhibitor, indicating the probable involvement of plasmin in KI03-induced proteolysis in UHT-treated milk. Equally extensive proteolysis occurred in serum protein-free casein micelle systems (SPFCM), with or without KI03, during storage at 37 °C following UHT treatment, indicating a role for whey proteins in KI03-induced proteolysis. Addition of β-lactoglobulin (β-lg) to a SPFCM system inhibited proteolysis, but extensive proteolysis occurred in a SPFCM system containing both β-lg and KI03. MPA-free Na caseinate (prepared by heating at 140 °C for 7 min) underwent extensive proteolysis when treated with plasmin before UHT treatment; proteolysis was inhibited by addition of °-lg to this system and KI03 reversed the inhibitory effect of β-lg. Plasmin proteolysis of isolated αs1-casein was inhibited by denatured β-lg (90 °C/30 min) at a level of 4 mg/ml but not by native β-lg. When denatured in the presence of KI03, β-lg had a lower free SH content than the control and was less inhibitory for plasmin in proteolysis of isolated αsl-casein. The results show that denatured β-lg inhibits plasmin proteolysis of caseins in UHT milk and that inhibition is prevented by KI03. This inhibition may occur via thiol–disulphide interchange, which is prevented if the SH group of ²-lg is oxidized by KI03, thus permitting the stimulatory effect of KI03 on proteolysis in UHT-treated milk.

Study of Degradation of Phenol by Fenton Reagent under Sunlight

2012 ◽  
Vol 610-613 ◽  
pp. 1364-1367
Author(s):  
Sheng Tao Jiang ◽  
Xiao Chen ◽  
Wei Su ◽  
Tian Fei Tang
Keyword(s):  
Visible Light ◽  
Ph Value ◽  
Phenol Degradation ◽  
Inhibitory Effect ◽  
Sodium Oxalate ◽  
Optimum Conditions ◽  
Fenton Reagent ◽  
Initial Phenol Concentration ◽  
High Concentrations ◽  
Phenol Wastewater

Degradation of phenol was studied in the presence of Fenton Reagent. The initial concentrations of C2O42, H2O2 , Fe2 + and pH value on the reaction were investigated. The optimum conditions to degrade phenol from water were determined when initial phenol concentration was 500mg/L, the concentration of Na2C2O4, H2O2 and Fe2 + were 0mmol/L, 300mg/L and 60mg/ L respectively, and pH value was 3. Under the optimum conditions, phenol degradation and mineralization rates could reach 80% and 50%, respectively when the degrade time lasted 10 min.Reference to other literature of sodium oxalate to join can effectively improve the utilization of the ultraviolet and visible light,thus enhancing the effect of high concentrations of phenol wastewater removal, but this experiment reflects the high C2O42- will play an inhibitory effect .

Decolorization of Mordant Red 15 Dye in Water by Potassium Ferrate (VI)

2013 ◽  
Vol 838-841 ◽  
pp. 2445-2448 ◽  
Author(s):  
Zheng Hua Wang ◽  
Bo Zhi Ren ◽  
Pu Wang
Keyword(s):  
Reaction Time ◽  
Fenton Reaction ◽  
Ph Value ◽  
Removal Rate ◽  
Dye Decolorization ◽  
High Ability ◽  
Potassium Ferrate ◽  
Optimum Conditions ◽  
Ph Values ◽  
Optimum Ph

Decolorization of the Mordant red 15 dye in water was investigated in laboratory-scale experiments using potassium ferrate (VI). The effect of corresponding parameters such as reaction time, concentration of potassium ferrate, pH values and the addition of H2O2 were considered in the experiments. The results indicated that about 78% dye decolorization was obtained in less than 30 min under optimum conditions. The pH values and concentration of ferrate (VI) were correlated with color removal rate of Mordant red 15 dye. The optimum pH value and ferrate (VI) concentration are 5 and 450 mg/L, respectively. Addition of H2O2 could initiate the Fenton reaction and result in 84.46% decolorization of dye in 30 min. Due to high ability of oxidizing and flocculation, potassium ferrate (VI) is an effect way for treatment of dyes in water.

Alkaline phosphatase. I. Kinetics and inhibition by levamisole of purified isoenzymes from humans.

1976 ◽  
Vol 22 (7) ◽  
pp. 972-976 ◽  
Author(s):  
H Van Belle
Keyword(s):  
Alkaline Phosphatase ◽  
Substrate Concentration ◽  
Human Liver ◽  
Alkaline Phosphatases ◽  
Mechanism Of Inhibition ◽  
Optimum Ph ◽  
Alkaline Phosphatase Isoenzymes

Abstract I studied the kinetics and sensitivity toward inhibition by levamisole and R 8231 of the most important human alkaline phosphatase isoenzymes. N-Ethylaminoethanol proved superior to the now widely used diethanolamine buffer, especially for the enzymes from the intestine and placenta, behaving as an uncompetitive activator. The optimum pH largely depends on the substrate concentration. The addition of Mg2+ has no effect on the activities. The meaning of Km-values for alkaline phosphatases is questioned. Isoenzymes from human liver, bone, kidney, and spleen are strongly inhibited by levamisole or R 8231 at concentrations that barely affect the enzymes from intestine or placenta. The inhibition is stereospecific, uncompetitive, and not changed by Mg2+. Inhibition is counteracted by increasing concentrations of N-ethylaminoethanol. The mechanism of inhibition is suggested to be formation of a complex with the phosphoenzyme.

ENZYMIC CHANGES IN THE CERVIX OF THE RAT AND HAMSTER DURING THE OESTROUS CYCLE AND THE EFFECT OF STEROIDS

1977 ◽  
Vol 72 (2) ◽  
pp. 153-161 ◽  
Author(s):  
ELIZABETH ZACHARIAH ◽  
N. R. MOUDGAL
Keyword(s):  
Alkaline Phosphatase ◽  
Specific Activity ◽  
Protein Biosynthesis ◽  
Hydrolytic Enzymes ◽  
Maximal Activity ◽  
Inhibitory Effect ◽  
Oestrous Cycle ◽  
Single Subcutaneous Injection ◽  
Arylsulphatase A ◽  
Phosphatase Alkaline

SUMMARY Changes in four hydrolytic enzymes, namely acid phosphatase, alkaline phosphatase, arylsulphatase A and B, of the cervix of the rat and hamster have been studied during the 4-day oestrous cycle. All four enzymes showed maximal activity on the day of oestrus and least activity on day 2 of dioestrus. All the enzymes showed significant reduction of activity after ovariectomy, arylsulphatase A and B showing the earliest changes in specific activity. A single subcutaneous injection of 0·02 μg oestradiol-17β/rat increased the specific activity of arylsulphatase A and B from the low ovariectomized level to that observed in control oestrous animals within 18 and 6 h respectively. A higher concentration of oestradiol-17β (2·0 μg) had an inhibitory effect. Progesterone was without effect on arylsulphatase B activity, but when given (2·0 mg) with 0·02 μg oestradiol-17β, it inhibited the response to oestrogen. Cycloheximide prevented the rise in arylsulphatase B activity occurring after oestrogen injection, suggesting a regulation of cervical arylsulphatase B at the level of protein biosynthesis. These results suggest that arylsulphatase B activity may be induced by oestrogen in the cervix of the rat.

Screening and Desilication of a Silicate Bacteria

2011 ◽  
Vol 236-238 ◽  
pp. 253-257
Author(s):  
Xian Zhen Zhang ◽  
De Si Sun ◽  
Hai Lin
Keyword(s):  
Particle Size ◽  
Incubation Time ◽  
Ph Value ◽  
Solution Temperature ◽  
Optimum Conditions ◽  
Initial Ph ◽  
Silicate Bacteria ◽  
Bauxite Ore

The strain Jgj-1 was isolated from Gaoan bauxite ore. The relations of desilication of the strain Jgj-1 and the pH of solution, temperature, shaking speed, incubation time, particle size were investigated. The results shows the optimum conditions of bioleaching are as following: at 28°C, initial pH value is 7.2, particle size 0.056mm, 200rpm shaking speed, incubation 5-7 days.

Charakterisierung und Kinetik des in der Rattenplacenta vorkommenden mikrosomalen Enzyms, das den Wasserstoff-Transfer von Oestradiol auf Androstendion katalysiert / Characterization and Kinetics of the Microsomal Enzyme of Rat Placenta which Functions as a “Transhydrogenase” between Estradiol-17β and Androstenedione

1971 ◽  
Vol 26 (7) ◽  
pp. 710-719 ◽  
Author(s):  
Kunhard Pollow ◽  
Barbara Pollow
Keyword(s):  
Hydrogen Transfer ◽  
Microsomal Fraction ◽  
Close Relation ◽  
Inhibitory Effect ◽  
Magnesium Ions ◽  
Michaelis Constant ◽  
Temperature Optimum ◽  
Optimum Ph ◽  
Kinetics Of ◽  
Estradiol 17Β

The microsomal fraction of rat placenta contains a 17β-hydroxysteroid-oxidoreductase which transfers hydrogen from position 17 of estradiol to androstenedione. This hydrogen transfer is dependent on NAD, NADP as cofactor is without effect. The optimum pH is at 6,9. In the presence of NAD the Michaelis constant for estradiol is 4,17 · 10-5м at pH 7,4. In the presence of androstenedione in the incubation medium the Km-value for estradiol is decreased, which indicates an increased affinity for the enzyme. The temperature optimum of the enzyme is 38 °C. Addition of SH-blocking agents inhibited the enzyme activity. Zinc and magnesium ions had an inhibitory effect on the “transhydrogenase” and B-NADPT specifically labelled from [1-T]-glucose showed that the non-effect of NADP on transhydrogenation from estradiol to androstenedione resulting in reduction of position 17 is not due to different stereospecifity.The results show a close relation between the oxidative metabolism of estradiol and the reduction of androstenedione, indicating that estradiol-17β, as the preferred hydrogen-donating substrate, is an essential component of the androstenedione-hydrogenating system in the microsomal fraction of rat placenta.

scholarly journals A Comparative Study of Fe (II) Ion Adsorption onto Chemically Activated Banana Peel and Sawdust Bio-adsorbent

2018 ◽  
Vol 6 (2) ◽  
pp. 137-141
Author(s):  
Suman Lal Shrestha
Keyword(s):  
Ph Value ◽  
Banana Peel ◽  
Ion Adsorption ◽  
Ferrous Ions ◽  
Adsorption Models ◽  
Freundlich Isotherms ◽  
Adsorption Capacities ◽  
Time Period ◽  
Optimum Ph ◽  
Different Types

The adsorption capacity of ferrous ions onto bio-sorbents prepared from two different types of bio-waste of banana peel (CABP) and sawdust (CASD) treated with sulfuric acid was studied using Langmuir and Freundlich isotherms. Result shows that the optimum pH value for about 99 % Fe (II) adsorption onto the CABP and CASD was found to be 3 and 4, respectively, after 5 hours or more contact time period. Both the Langmuir and Freundlich adsorption models are fitted to remove the Fe (II) ions from aqueous solution by the bio-adsorbent of CABP and CASD. The maximum adsorption capacities for the CABP and CASD were found to be about 34 and 116 mg/g, respectively. These results showed that the CASD seems to be more effective bio-adsorbent than the CABP to remove the Fe (II) ions from drinking or/and wastewaters.Int. J. Appl. Sci. Biotechnol. Vol 6(2): 137-141 

The dynamics of individual whey protein concentrations in cows’ mammary secretions during the colostral and early lactation periods

2018 ◽  
Vol 86 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Raquel F.S. Raimondo ◽  
Juliana S.P. Ferrão ◽  
Samantha I. Miyashiro ◽  
Priscila T. Ferreira ◽  
João Paulo E. Saut ◽  
...  
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Whey Proteins ◽  
Total Proteins ◽  
Mature Milk ◽  
Rennet Coagulation ◽  
Sds Page ◽  
Different Types ◽  
Biuret Method ◽  
Jersey Cows ◽  
Β Lactoglobulin

AbstractThe bovine whey consists of more than 200 different types of proteins, of which β-lactoglobulin, α-lactalbumin, serum albumin, immunoglobulins and lactoferrin predominate. However, their concentrations are not stable due to the existence of protein dynamics during a transition from colostrum secretion to mature milk. To evaluate the dynamics of whey proteins of Jersey cows during a colostral phase and first month of lactation and an influence of the number of lactations, 268 milk samples from 135 Jersey cows were selected through a clinical evaluation. Whey was obtained by rennet coagulation of the mammary secretion. The concentration of total proteins was determined by the biuret method and their fractions were identified by 12% dodecyl sulfate-polyacrylamide gel electrophoresis (12% SDS-PAGE). Maximum concentrations of all protein fractions were observed in the first 12 h of lactation, reducing over the course of the study. Modification of the protein predominance was also observed. The transition from colostrum secretion to milk occurred between 24 and 72 h postpartum. There was an influence of the number of lactations on the dynamics of whey proteins, indicating that multiparous cows had better immunological and nutritional quality when compared to primiparous cows.

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