Enzymatic Assay for the Combined Determination of Plasmin Plus Plasminogen in Milk: Revisited

Politis, I.; Zavizion, Boris; Barbano, D.M.; Gorewit, R.C.

doi:10.3168/jds.s0022-0302(93)77455-x

Cited by 49 publications

(47 citation statements)

References 15 publications

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“…Glucocorticoids inhibit u-PA action and less markedly that of t-PA [20]. BSA, whose level is increased by 1427% during mastitis [23] has an inhibitory effect (25 to 65% inhibition) on both plasmin and plasminogen activities [58]. The same effects were observed for b-lactoglobulin and a-lactalbumin by the same authors.…”

Section: Plasmin Activity (Tab Vi)mentioning

confidence: 54%

Polymorphonuclear proteolytic activity and milk composition change

Roux¹,

Laurent²,

Moussaoui³

2003

Vet. Res.

118

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-Relationships between Quarter Milk Cell Count (QMCC) and Tank Milk Cell Count (TMCC) with milk biochemical and technological parameters in milk and dairy products were investigated. All parameters measured were affected by the increase of TMCC and QMCC between 0 and 600 000 cells/mL. The variable effect of lactation stage which is different for different authors, is discussed. The three mechanisms, measured during the inflammation of the udder, implicated in the modification of milk quality are described (a decrease in synthesis, a decrease in the milk barrier permeability and an increase in proteolytic activities). The direct effect of plasmin in caseinolysis is well known; the specific role of the increase of somatic cells (especially PMN) in the modification of milk quality is described. Several specific proteolytic activities of PMN are described and the impact of these activities on caseinolysis is evaluated. Two hypothetical mechanisms of caseinolysis by PMN are suggested and a synthetic scheme of the role of plasmin, bacteria and somatic cells in caseinolysis is discussed. caseinolysis / mastitis / milk / PMN proteases / SCC

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Section: Plasmin Activity (Tab Vi)mentioning

confidence: 54%

Polymorphonuclear proteolytic activity and milk composition change

Roux¹,

Laurent²,

Moussaoui³

2003

Vet. Res.

118

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“…The weak I~-casein band could have been due to the 3% FBS in the medium. Plasmins, which are present in serum, hydrolyze c~ scasein and 13-casein but not k-casein (27). k-Casein holds the casein micelles containing cq-casein and 13-casein in colloidal suspension and protects them from precipitation by calcium ions (23,33).…”

Section: Resultsmentioning

confidence: 99%

Bovine mammary explant versus primary cell cultures: Effect of bovine somatotropin and insulinlike growth factor-I on DNA content and protein synthesis

Keys

Cifrian²,

Guidry³

et al. 1997

In Vitro Cell.Dev.Biol.-Animal

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Cellular DNA, milk protein content, and protein secretion by bovine mammary explants were compared to cultures of confluent and growing primary bovine mammary secretory cells over 4 d. Explants were obtained at slaughter from eight Holstein cows (120 +/- 35 d lactation). Primary cells were grown to confluence, cryopreserved, thawed, and cultured through five passages. Explants and cells were cocultured with liver and adipose tissue in the presence of somatotropin, insulin-like growth factor-I, and somatotropin + insulin-like growth factor-I. Cellular DNA and milk proteins were assayed using fluorescent probes and flow cytometry. Media proteins were assayed by densitometer scanning of electrophoresis gel bands. DNA content of explant, confluent, and growing primary cells increased similarly through the 96 h incubation. DNA content in G0G1 phase was increased by: (a) insulin-like growth factor-I in explant cells; (b) somatotropin, insulin-like growth factor-I, and their combination in confluent primary cells; and (c) the combination of somatotropin and insulin-like growth factor in growing primary cells. Approximately 65% of explant and confluent primary cells were in the G0G1 or differentiated phase compared to 47% for the growing primary cells. Whey protein content and secretion were similar among cell types. Explant cells contained and secreted more beta-casein than primary cells but secretion trends for beta-casein and k-casein were similar after 48 h for both cell types. Results suggest that primary cell cultures are comparable to explant cultures when used to study mechanisms of DNA and milk protein synthesis and secretion.

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“…In brief, 10 g of grated cheese were mixed with 90 mL of trisodium citrate 0.1 mol.L −1 containing 12 mmol.L −1 ε-aminocaproic acid (EACA). This low concentration of EACA (~11 mM) facilitates the dissociation of plasmin/plasminogen from the micelles and its migration to the soluble phase (Politis et al 1993).…”

Section: Measurement Of Plasmin Activitymentioning

confidence: 99%

Proteolysis and related enzymatic activities in ten Greek cheese varieties

Nega

Moatsou

2011

Dairy Science & Technol.

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The objective of this study was to assess indices of proteolysis and related enzymatic activities of various cheese varieties produced in Greece. Physicochemical composition, extent of proteolysis (nitrogen fraction and reversed-phase high-performance liquid chromatography (RP-HPLC) profiles of cheese soluble fraction) and residual chymosin and plasmin activities were analyzed in 57 commercial samples, grouped according to cheesemaking technologies. The mean values of soluble nitrogen fraction on total nitrogen and trichloroacetic acid-soluble nitrogen fraction on total nitrogen did not differ significantly between the different cheese varieties, with mean values of 16.03% and 9.97%, respectively. Brined cheeses had the highest mean residual chymosin activity 0.166 International Milk Clotting units (IMCU).g −1 of cheese dry matter and the lowest mean plasmin plus plasminogen-derived activity 3.88 U.g −1 of cheese. The respective values for Gruyère and hard type cheeses were 0.029 and 0.047 IMCU.g −1 of cheese dry matter for chymosin and 6.22 and 6.94 U.g −1 of cheese for plasmin. It was interesting that both enzymatic activities were high in pasta filata type cheeses, i.e., respective mean values of 0.086 IMCU. g −1 of cheese dry matter and 7.42 U.g −1 of cheese. Intermediate regions on the RP-HPLC profiles were positively correlated with residual chymosin activity and negatively correlated with plasmin activity. It was concluded that cooking at pH close to cheesemilk pH and pressing are the most important technological factors both for proteolysis and activity of major proteolytic enzymes in various cheese varieties.

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Enzymatic Assay for the Combined Determination of Plasmin Plus Plasminogen in Milk: Revisited

Cited by 49 publications

References 15 publications

Polymorphonuclear proteolytic activity and milk composition change

Polymorphonuclear proteolytic activity and milk composition change

Bovine mammary explant versus primary cell cultures: Effect of bovine somatotropin and insulinlike growth factor-I on DNA content and protein synthesis

Proteolysis and related enzymatic activities in ten Greek cheese varieties

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