Some Functional Properties of an Enzymatically Phosphorylated Cowpea (<i>Vigna unguiculata)</i>Globulin Isolate

Aluko, Rotimi E.; Yada, Rickey Y.

doi:10.1271/bbb.59.2207

Cited by 5 publications

(5 citation statements)

References 10 publications

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“…The increased solubility of the phosphorylated protein when compared to the untreated protein is in agreement with the I max result shown in Table 1, i.e., increased interactions between the aro-matic residues and decreased exposure of the residues to the polar solvent as a result of phosphorylation. Similar results showing improved protein solubility as a result of enzymatic phosphorylation have been reported for soybean protein isolate (Campbell et al, 1992;Shih and Campbell, 1993) and cowpea protein isolate (Aluko and Yada, 1995a).…”

Section: Methodssupporting

confidence: 84%

“…The serine and threonine kinases are the most widely used enzymes in food protein modification, since proteins containing oxygen-bound phosphate are more stable under acid conditions than the nitrogen-bound phosphate (Matheis and Whitaker, 1984). The enzymatic reaction is highly specific and results in a phos-phorylated protein with higher solubility, greater waterholding capacity or greater calcium-binding capacity (Seguro and Motoki, 1990;Campbell et al, 1992;Aluko and Yada, 1995a). The increase in solubility is particularly prominent in the pH range near the isoelectric point where proteins exhibit the least solubility (Ross, 1989).…”

Section: Introductionmentioning

confidence: 99%

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Structural and Functional Properties of a Partially Purified Cowpea (Vigna unguiculata) Globulin Modified with Protein Kinase and Glycopeptidase

Aluko

Yada

Lencki

et al. 1997

J. Agric. Food Chem.

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The major globulin fraction in cowpea seed was partially purified by selective ammonium sulfate precipitation and gel chromatography. The partially purified protein was enzymatically phosphorylated or deglycosylated. Phosphate content increased from 5.81 μg/mg in the untreated protein to 10.55 μg/mg in the protein kinase treated protein. Fluorescence intensity and protein solubility were significantly (p ≤ 0.05) increased at pH 3−8 as a result of phosphorylation, while susceptibility to heat-induced coagulation was significantly (p ≤ 0.05) decreased. At 50% deglycosylation, fluorescence intensity was significantly (p ≤ 0.05) higher for the untreated protein than the treated protein. The intensity of the near-UV circular dichroism spectra of the deglycosylated protein was lower than that of the untreated protein at pH 3, 4, and 6, whereas the reverse was observed at pH 7 and 8. The deglycosylated protein was less soluble at pH 3, 4, 7, and 8 and was more susceptible to heat coagulation when compared to the untreated protein. Modification by protein kinase would allow use in foods where greater solubility is needed, while deglycosylation could enhance utilization in foods that require heat-induced coagulation. Keywords: Cowpea globulin; phosphorylation; deglycosylation; functional properties; physicochemical properties

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Section: Methodssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Structural and Functional Properties of a Partially Purified Cowpea (Vigna unguiculata) Globulin Modified with Protein Kinase and Glycopeptidase

Aluko

Yada

Lencki

et al. 1997

J. Agric. Food Chem.

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“…Protein solubility was determined according to a previously described method (Aluko and Yada 1995). Emulsifying activity index (EAI) and emulsion stability were determined according to the method of Pearce and Kinsella (1978).…”

Section: Functional Propertiesmentioning

confidence: 99%

“…Functional properties were determined by dispersing the samples in disodium hydrogen phosphate solutions that had been adjusted to pH 3 to 8 with 0.1 M HCl solution. Protein solubility was determined according to a previously described method (Aluko and Yada 1995). Emulsifying activity index (EAI) and emulsion stability were determined according to the method of Pearce and Kinsella (1978).…”

Section: Functional Propertiesmentioning

confidence: 99%

Functional and Bioactive Properties of Quinoa Seed Protein Hydrolysates

Aluko¹,

Monu²

2003

Journal of Food Science

229

128

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Quinoa protein concentrate was hydrolyzed with alcalase to obtain a hydrolysate that was fractionated by ultrafiltration using 10000-and 5000-molecular-weight cutoff membranes. Functional properties of the protein concentrate, protein hydrolysate, and membrane permeates were compared at different pH values. Protein solubility of the hydrolysate and membrane permeates were significantly higher (P = 0.05) than that of the protein concentrate. The protein concentrate had a significantly higher (P = 0.05) emulsifying activity index than the protein hydrolysate and membrane permeates. Membrane fractionation of the protein hydrolysate into lower-molecularweight peptides significantly reduced (P = 0.05) foaming properties, but it improved radical scavenging activity and the ability to inhibit the activity of angiotensin-converting enzyme.

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“…From the study of the sequences of different legume proteins, it was found that not all phosphorylatable target amino acids were phosphorylated in vitro (Chardot et al, 1998b). Enzymatically phosphorylated legume proteins exhibited new functional properties with respect to the nonphosphorylated ones (Ross and Bathnagar, 1989a,b;Seguro and Motoki, 1989;Campbell et al, 1992;Aluko and Yada, 1995;Ralet et al, 1996;Chardot et al, 1998b). Chemically or enzymatically dephosphorylated caseins have been used as model substrates for the study of the kinetic properties of protein kinases for a long time (Walsh et al, 1968), but little work has been done on the enzymatic phosphorylation of individual caseins (Hataway and Traugh, 1984;Yoshikawa et al, 1989), especially to achieve stoichiometric phosphate incorporation (Chardot et al, 1998b).…”

Section: Introductionmentioning

confidence: 99%

Overphosphorylation of Milk Caseins by a Recombinant Protein Kinase CK2 Catalytic Subunit

Pitois

Chardot

Meunier

1999

J. Agric. Food Chem.

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Milk caseins have been phosphorylated by a recombinant protein kinase CK2 catalytic subunit from Schizosaccharomyces pombe (rspCK2alpha). Phosphate incorporation stoechiometries into purified caseins and into native phosphocaseinate, a substrate exhibiting a micellar-like structure, were determined. We incorporated 2.01 mol of P/mol of alpha-casein, 6.46 mol of P/mol of beta-casein, up to 0. 29 mol of P/mol of kappa-casein in 4 h, and more than 1.36 mol of P/mol of casein into phosphocaseinate under optimized conditions. Phosphocaseinate was sequentially phosphorylated; beta-caseins being labeled at first; alpha-caseins being labeled later; and to a lower extend, kappa-caseins were the last to be phosphorylated. The solubility of phosphocaseinate micelles increased by 1.34 from 65 to 87%, and its rennetting time was increased 2.88 times. These results are discussed in terms of plausible structural organization of caseins micelles and the effect of phosphorylation on their structure.

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Some Functional Properties of an Enzymatically Phosphorylated Cowpea (Vigna unguiculata)Globulin Isolate

Cited by 5 publications

References 10 publications

Structural and Functional Properties of a Partially Purified Cowpea (Vigna unguiculata) Globulin Modified with Protein Kinase and Glycopeptidase

Structural and Functional Properties of a Partially Purified Cowpea (Vigna unguiculata) Globulin Modified with Protein Kinase and Glycopeptidase

Functional and Bioactive Properties of Quinoa Seed Protein Hydrolysates

Overphosphorylation of Milk Caseins by a Recombinant Protein Kinase CK2 Catalytic Subunit

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