The purification and properties of an amino acid arylamidase from bovine milk

1969 ◽  
Vol 47 (2) ◽  
pp. 173-178 ◽  
Author(s):  
A. Mellors
Keyword(s):  
Amino Acid ◽  
Milk Fat ◽  
Specific Activity ◽  
Bovine Milk ◽  
Deae Cellulose ◽  
Maximum Activity ◽  
Divalent Metal Ions ◽  
Purification And Properties ◽  
Milk Fat Globule ◽  
High Concentrations

An amino acid arylamidase is present in bovine milk and is associated with the "microsomes" of the milk-fat globule membrane. It has been purified by DEAE-cellulose chromatography of a 0.1 M NaCl extrast of milk microsomes. The specific activity of the purified arylamidase was increased 12 700-fold over that of the milk. Three peaks of arylamidase activity could be recognized after the chromatography. One form was apparently bound to casein. The major peak of arylamidase activity hydrolyzes lysyl-, alanyl-, valyl-, and arginyl-β-naphthylamides at similar rates, with little activity against glycyl- and histidyl-β-naphthylamides. The arylamidase requires the restoration of sulfhydryl groups by dithiothreitol for maximum activity. It is inhibited by EDTA and some divalent metal ions, and only calcium ions restore the EDTA-inactivated enzyme. The optimum pH for the hydrolysis of lysyl-β-naphthylamide is pH 7.7, and high concentrations of this substrate are inhibitory.

Glycosidases in bovine milk: α-mannosidase and its inhibition by zwitterions

1968 ◽  
Vol 46 (11) ◽  
pp. 1351-1356 ◽  
Author(s):  
A. Mellors ◽  
V. R. Harwalkar
Keyword(s):  
Amino Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Bovine Milk ◽  
Maximum Activity ◽  
Manganese Ions ◽  
Ammonium Sulfate Precipitation ◽  
Optimum Ph ◽  
High Concentrations ◽  
Hydrolysis Of ◽  
Dibasic Amino Acids

α-Mannosidase is present in bovine milk and is associated with the β-casein fraction following polyacrylamide gel electrophoresis. It was separated from the casein complex by ammonium sulfate precipitation in the presence of 10% (v/v) ethanol. Zinc or manganese ions are required for maximum activity and the enzyme is very labile. The optimum pH for the hydrolysis of p-nitrophenyl α-mannoside is about 3. In the presence of amino acid buffers the enzyme is inhibited. For dibasic amino acids this inhibition is inversely related to the [Formula: see text] of the amino acid and is apparently due to inhibition by zwitterions. High concentrations of the substrate p-nitrophenyl α-mannoside are inhibitory, and the apparent Km for this hydrolysis is 1.2 mM.

Production and characterization of monoclonal antibodies directed against bovine milk fat globule membrane (MFGM)

1994 ◽  
Vol 1199 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Naohito Aoki ◽  
Hidenori Kuroda ◽  
Miho Urabe ◽  
Yoshimi Taniguchi ◽  
Takahiro Adachi ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Milk Fat ◽  
Bovine Milk ◽  
Milk Fat Globule Membrane ◽  
Milk Fat Globule ◽  
Fat Globule

Chemical changes in bovine milk fat globule membrane caused by heat treatment and homogenization of whole milk

2002 ◽  
Vol 69 (4) ◽  
pp. 555-567 ◽  
Author(s):  
SUNG JE LEE ◽  
JOHN W. SHERBON
Keyword(s):  
Heat Treatment ◽  
Membrane Proteins ◽  
Milk Fat ◽  
Whey Proteins ◽  
Bovine Milk ◽  
Chemical Changes ◽  
Milk Fat Globule Membrane ◽  
Whole Milk ◽  
Milk Fat Globule ◽  
Fat Globule

The effects of heat treatment and homogenization of whole milk on chemical changes in the milk fat globule membrane (MFGM) were investigated. Heating at 80 °C for 3–18 min caused an incorporation of whey proteins, especially β-lactoglobulin (β-lg), into MFGM, thus increasing the protein content of the membrane and decreasing the lipid. SDS-PAGE showed that membrane glycoproteins, such as PAS-6 and PAS-7, had disappeared or were weakly stained in the gel due to heating of the milk. Heating also decreased free sulphydryl (SH) groups in the MFGM and increased disulphide (SS) groups, suggesting that incorporation of β-lg might be due to association with membrane proteins via disulphide bonds. In contrast, homogenization caused an adsorption of caseins to the MFGM but no binding of whey proteins to the MFGM without heating. Binding of caseins and whey proteins and loss of membrane proteins were not significantly different between milk samples that were homogenized before and after heating. Viscosity of whole milk was increased when milk was treated with both homogenization and heating.

scholarly journals Acetylcholinesterase aus Rindererythrozyten. Reinigung und Eigenschaften des mit und ohne Triton X-100 solubilisierten Enzyms / Acetylcholinesterase from Bovine Erythrocytes. Purification and Properties of the En­zyme Solubilized in the Presence and the Absence of Triton X-100

1979 ◽  
Vol 34 (9-10) ◽  
pp. 721-725 ◽  
Author(s):  
Heinz Großmann ◽  
Manfred Liefländer
Keyword(s):  
Amino Acid ◽  
Specific Activity ◽  
Multiple Forms ◽  
Terminal Amino Acid ◽  
Enzyme Preparations ◽  
Purification And Properties ◽  
Solubilized Enzyme ◽  
Terminal Amino ◽  
Triton X ◽  
Bovine Erythrocytes

Abstract Acetylcholinesterase was released from bovine erythrocytes by Triton X-100 treatment and pu­rified by twofold affinity chromatography. The detergentfree enzyme was obtained with a specific activity of 4130 U /mg (303 000-fold purification) and a 25% yield. Alternatively, the commercial available crude enzyme was purified. The latter preparation has an uniform molecular weight (Mr 175 000). The Triton-solubilized enzyme, however, can be resolved after removal of the detergent in eight multiple forms (Mr 175 000 and multiple values), in the presence of Triton there exists only one form (Mr 338 000). The amino acid composition of the two enzyme preparations differs significantly. No differences were observed with respect to other properties: SDS gel electrophore­sis revealed two protein bands (Mr 166 000 and 86 000) with both preparations. The enzyme is a glycoprotein with a pI value of 4.3 and contains strongly bound phosphatidylethanolamine. The N-terminal amino acid has been found to be Glu (or Gin).

scholarly journals Safety and Tolerance Evaluation of Milk Fat Globule Membrane-Enriched Infant Formulas: A Randomized Controlled Multicenter Non-Inferiority Trial in Healthy Term Infants

2014 ◽  
Vol 8 ◽  
pp. CMPed.S16962 ◽  
Author(s):  
Claude Billeaud ◽  
Giuseppe Puccio ◽  
Elie Saliba ◽  
Bernard Guillois ◽  
Carole Vaysse ◽  
...  
Keyword(s):  
Weight Gain ◽  
Milk Fat ◽  
Bovine Milk ◽  
Control Group ◽  
Infant Formulas ◽  
Term Infants ◽  
Milk Fat Globule Membrane ◽  
Standard Formula ◽  
Milk Fat Globule ◽  
Fat Globule

Objective This multicenter non-inferiority study evaluated the safety of infant formulas enriched with bovine milk fat globule membrane (MFGM) fractions. Methods Healthy, full-term infants ( n = 119) age ≤14 days were randomized to standard infant formula (control), standard formula enriched with a lipid-rich MFGM fraction (MFGM-L), or standard formula enriched with a protein-rich MFGM fraction (MFGM-P). Primary outcome was mean weight gain per day from enrollment to age 4 months (non-inferiority margin: –3.0 g/day). Secondary (length, head circumference, tolerability, morbidity, adverse events) and exploratory (phospholipids, metabolic markers, immune markers) outcomes were also evaluated. Results Weight gain was non-inferior in the MFGM-L and MFGM-P groups compared with the control group. Among secondary and exploratory outcomes, few between-group differences were observed. Formula tolerance rates were high (>94%) in all groups. Adverse event and morbidity rates were similar across groups except for a higher rate of eczema in the MFGM-P group (13.9% vs control [3.5%], MFGM-L [1.4%]). Conclusion Both MFGM-enriched formulas met the primary safety endpoint of non-inferiority in weight gain and were generally well tolerated, although a higher rate of eczema was observed in the MFGM-P group.

Purification and properties of glutamate-phenylpyruvate aminotransferase from the ruminal protozoan Entodinium caudatum

2004 ◽  
Vol 55 (9) ◽  
pp. 991
Author(s):  
Md. Ruhul Amin ◽  
Ryoji Onodera ◽  
R. Islam Khan ◽  
R. John Wallace ◽  
C. Jamie Newbold
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Maximum Activity ◽  
Purification And Properties ◽  
Sds Page ◽  
Wide Range ◽  
S 100 ◽  
A Cell

Entodinium species are important in catabolic protein metabolism by the mixed ruminal microbial population. This study was conducted to purify, and investigate properties of one of the enzymes involved in amino acid metabolism by Entodinium caudatum, glutamate-phenylpyruvate aminotransferase (GPA; EC 2.6.1.64). GPA was purified 74-fold from a cell-free extract by ammonium sulfate precipitation and column chromatography with phenyl-superose, DEAE-Toyopearl 650M, Sephacryl S-100 HR, and Sephadex G-100. The molecular mass of GPA was estimated by SDS–PAGE to be 65.0 kDa. The optimum pH was 6.0 and it was found to be reactive over a wide range of pH from 5.0 to 10.5. Maximum activity of GPA occurred at 45°C and the activity declined at temperatures over 55°C. GPA was stable below 60°C. Aminooxyacetate and phenylhydrazine were highly inhibitory, and SDS, EDTA, and some heavy metal ions also inhibited activity. The purification and characterisation of the enzyme will help to isolate the gene and ultimately to understand the role of GPA in both anabolic and catabolic amino acid metabolism by Entodinium caudatum.

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