| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Laboratoire de Biochimic et Technologie Laitières and Laboratoire de Physiologie de la Lactation, Institut National de la Recherche Agronomique, C.N.R.Z., 78350 Jouy-en-Josas, France
ABSTRACT
Plasmin and plasminogen-derived activities were measured in bovine and human skim milk with a chromogenic tripeptide H-D-valyl-L-leucyl-L-lysine-p-nitroanilide substrate. One unit of enzyme activity was defined as the amount of plasmin or urokinase-activated plasminogen that produced a change of absorbance at 450 nm of .001 in 1 min at pH 7.4 and 37°C under the described reaction conditions. By this definition, about 4 to 5 units of plasmin were in 1 ml of bovine milk at both early (2 to 3 mo) and late (7 to 8 mo) lactation. However, plasminogen-derived activity was 45.3 ± 13.0 U/ml at the late state of lactation compared to only 26.3 ± 2.7 U/ml at the early stage. Human milk obtained on days 6 to 7-postpartum contained 4.8 ± 4.2 and 12.4 ± 9.9 U/ml of plasmin and plasminogen-derived activity. Upon pasteurization of bovine milk at 72°C for 15 s, both plasmin and plasminogen-derived activities decreased by about 10% whereas a commercial ultrahigh temperature sterilization destroyed plasmin activity to undetectable and plasminogen-derived activity by about 90%. By an assay based on fibrinolysis of iodine-125 labeled fibrin, a plasminogen-activator activity was associated with milk casein micelles whereas an inhibitor of a plasminogen-activator, plasmin, or both were localized in milk serum. Plasminogen-activator activity was diminished in the skim milk by about 80% compared to activity in the casein micelles, apparently due to naturally occurring inhibitors in milk serum. Quality of milk and dairy products may be influenced by amounts of proteolytic enzymes such as plasmin and factors affecting them.
1 Laboratoire de Physiologie de la Lactation.
This article has been cited by other articles:
|
|
 |
|
  A. Santillo and M. Albenzio Influence of Lamb Rennet Paste Containing Probiotic on Proteolysis and Rheological Properties of Pecorino Cheese J Dairy Sci, May 1, 2008; 91(5): 1733 - 1742. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Caroprese, A. Marzano, L. Schena, R. Marino, A. Santillo, and M. Albenzio Contribution of Macrophages to Proteolysis and Plasmin Activity in Ewe Bulk Milk J Dairy Sci, June 1, 2007; 90(6): 2767 - 2772. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Wang, K. D. Hayes, and L. J. Mauer Fluorescent Labeling Study of Plasminogen Concentration and Location in Simulated Bovine Milk Systems J Dairy Sci, January 1, 2006; 89(1): 58 - 70. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Albenzio, M. Caroprese, A. Santillo, R. Marino, L. Taibi, and A. Sevi Effects of Somatic Cell Count and Stage of Lactation on the Plasmin Activity and Cheese-Making Properties of Ewe Milk J Dairy Sci, March 1, 2004; 87(3): 533 - 542. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. R. Garcia-Risco, I. Recio, E. Molina, and R. Lopez-Fandino Plasmin Activity in Pressurized Milk J Dairy Sci, March 1, 2003; 86(3): 728 - 734. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
