Isolation and identification of further peptides in the diafiltration retentate of the water-soluble fraction of Cheddar cheese

1997 ◽  
Vol 64 (3) ◽  
pp. 433-443 ◽  
Author(s):  
TANOJ K. SINGH ◽  
PATRICK F. FOX ◽  
ÁINE HEALY

Several peptides were isolated from the diafiltration retentate, prepared using 10 kDa membranes, of the water-soluble extract from a commercial mature Cheddar cheese and identified by amino acid sequencing and mass spectrometry. Most of the peptides were from the N-terminal half of β-casein, but peptides from αs1- and αs2-caseins were also identified; the extract also contained α-lactalbumin. Identified peptides showed the important role played by lactococcal cell envelope proteinases in the degradation of primary proteolytic products from αs1- and β- caseins, produced by chymosin and plasmin respectively. Plasmin seemed to be involved in the hydrolysis of αs2-casein. Several phosphopeptides were identified and the action of phosphatase on these peptides was evident.

1995 ◽  
Vol 62 (4) ◽  
pp. 629-640 ◽  
Author(s):  
Tanoj K. Singh ◽  
Patrick F. Fox ◽  
Áine Healy

SUMMARYThe water-soluble extract of Cheddar cheese was fractionated by diafiltration using 10 kDa cut-off membranes. Peptides were isolated from the diafiltrate retentate by chromatography on DEAE-cellulose with a linear NaCl gradient in 50 mM-Tris-HCl, pH 8·6, and reversed-phase HPLC or electroblotting from urea-PAGE gels. Peptides were identified by determining N-terminal amino acid sequences and mass spectrometry. Most (45) of the total 51 peptides identified in the diafiltrate retentate originated from β-casein, especially from a short region in the N-terminal half of the molecule. Only six peptides originated from αs1-casein; β-lactoglobulin was also identified in the retentate. The origin of most of these peptides could be explained on the basis of known specificities of lactococcal cell envelope proteinases.


1991 ◽  
Vol 58 (3) ◽  
pp. 363-372 ◽  
Author(s):  
Dolores Gonzalez de Llano ◽  
M. Carmen Polo ◽  
Mercedes Ramos

SummaryThe blue cheese nitrogenous fractions soluble in water and in 5% phosphotungstic acid (PTA) were analysed by HPLC after 3–180 d ripening. In the water-soluble fraction, in addition to four or five major peaks corresponding to amino acids, there were many minor peaks, which increased during ripening. The low molecular mass peptides, soluble in 5% PTA, showed ripening-induced increments. A method combining precipitation with 5% PTA, gel permeation and subsequent HPLC was used to isolate some peptides of cheese. Four peptides containing between seven and ten residues were isolated and their amino acid composition and N-terminal residues determined.


2001 ◽  
Vol 68 (4) ◽  
pp. 675-688 ◽  
Author(s):  
ERWAN ENGEL ◽  
CHANTAL SEPTIER ◽  
NADINE LECONTE ◽  
CHRISTIAN SALLES ◽  
JEAN-LUC LE QUERE

The taste-active compounds of a Camembert cheese selected for its intense bitterness defect were investigated. The water-soluble fraction (WSE) was extracted with pure water and fractionated by successive tangential ultrafiltrations and nanofiltration. The physicochemical assessment of these fractions led to the construction of a model WSE which was compared by sensory evaluation to the crude water-soluble extract, using a panel of 16 trained tasters. As no significant difference was perceived, this model WSE was then used directly or mixed with other cheese components for omission tests. Among the main taste characteristics of the WSE (salty, sour, umami and bitter), bitterness was found to be due to small peptides whose mass distribution was obtained by RPHPLC-MS (400–3000 Da) and whose taste properties are discussed.


2021 ◽  
Vol 86 (2) ◽  
pp. 523-530
Author(s):  
Jiuliane Martins da Silva ◽  
Carlos Eduardo Barão ◽  
Erick Almeida Esmerino ◽  
Adriano Gomes Cruz ◽  
Tatiana Colombo Pimentel

2003 ◽  
Vol 228 (6) ◽  
pp. 749-758 ◽  
Author(s):  
Mirim Jin ◽  
Hyung Jin Jung ◽  
Jeong June Choi ◽  
Hyang Jeon ◽  
Jin Hwan Oh ◽  
...  

We isolated a water-soluble extract, PG101, from cultured mycelia of Lentinus lepideus. Treatment of human peripheral blood mononuclear cells (PBMCs) with PG101 increased levels of TNF-α, IL-1β, IL-10, and IL-12 by 100- to 1000-fold, whereas GM-CSF and IL-18 were activated by an order of magnitude. On the contrary, IFN-γ and IL-4 were not affected. The response to PG101 occurred in a dose- and time-dependent manner. From the human PBMCs treated with PG101, TNF-α was a first cytokine to be activated, detectable at 2 hr post-treatment followed by IL-1β at 6 hr post-treatment. IL-12 and IL-10 were the next to follow. GM-CSF and IL-18 both showed significant increases 24 hr after treatment. When PBMCs were sorted into various cell types, monocyte/macrophages, but not T and B cells, were the major target cell type responsive to PG101. Consistent with this result, the profile of cytokine expression upon PG101 treatment was comparable between PBMCs and a human promonocytic cell line (U937), whereas cell lines of T cell and myeloid origins did not respond to PG101. Data from a transient transfection assay involving specific reporter plasmids indicated that cellular transcription factor such as NF-κB, but not AP-1, was highly activated by PG101. Results from a gel retardation assay and the experiment involving a specific NF-κB inhibitor confirmed the involvement of NF-κB. Despite its significant biological effect on various cytokines, PG101 remained nontoxic in both rats and PBMCs even at a biological concentration approximately 20 times greater. PG101 demonstrates great potential as a therapeutic immune modulator.


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