scholarly journals Effect of surfaces on fluid-phase prekallikrein activation

Blood ◽  
1981 ◽  
Vol 57 (3) ◽  
pp. 553-560 ◽  
Author(s):  
CF Scott ◽  
EP Kirby ◽  
PK Schick ◽  
RW Colman

Abstract The activation of prekallikrein by factor XII fragments (XIIf), during incubation in plastic tubes was previously noted to be increased by high molecular weight (HMW) kininogen as well as other plasma proteins. In this report, we investigated the mechanism responsible for this increase. Although we confirmed that HMW kininogen, bovine serum albumin, fibrinogen, cold insoluble globulin, and mixed phospholipids apparently increased prekallikrein activation, we found that the product of prekallikrein activation (kallikrein) lost substantial activity in less than 0.5 min after exposure to a variety of fresh surfaces. This loss was partially prevented by the presence of various proteins and phospholipids. Similar protection against inactivation of XIIf, the enzyme in this reaction, was also found. In contrast, no loss of the substrate, prekallikrein, was observed during incubation. The loss of kallikrein activity was found to be proportional to the surface area of the incubation vessel as well as the concentration of kallikrein. Further loss of kallikrein activity could also be prevented by pretreating the vessel with kallikrein. We therefore conclude that various substances apparently affect prekallikrein activation in a purified system by preventing the enzyme and product in the reaction mixture from losing activity due to adsorption to a surface.

Blood ◽  
1981 ◽  
Vol 57 (3) ◽  
pp. 553-560
Author(s):  
CF Scott ◽  
EP Kirby ◽  
PK Schick ◽  
RW Colman

The activation of prekallikrein by factor XII fragments (XIIf), during incubation in plastic tubes was previously noted to be increased by high molecular weight (HMW) kininogen as well as other plasma proteins. In this report, we investigated the mechanism responsible for this increase. Although we confirmed that HMW kininogen, bovine serum albumin, fibrinogen, cold insoluble globulin, and mixed phospholipids apparently increased prekallikrein activation, we found that the product of prekallikrein activation (kallikrein) lost substantial activity in less than 0.5 min after exposure to a variety of fresh surfaces. This loss was partially prevented by the presence of various proteins and phospholipids. Similar protection against inactivation of XIIf, the enzyme in this reaction, was also found. In contrast, no loss of the substrate, prekallikrein, was observed during incubation. The loss of kallikrein activity was found to be proportional to the surface area of the incubation vessel as well as the concentration of kallikrein. Further loss of kallikrein activity could also be prevented by pretreating the vessel with kallikrein. We therefore conclude that various substances apparently affect prekallikrein activation in a purified system by preventing the enzyme and product in the reaction mixture from losing activity due to adsorption to a surface.


Parasitology ◽  
2003 ◽  
Vol 126 (1) ◽  
pp. 41-51 ◽  
Author(s):  
C. HÖLSCHER ◽  
R. HARTMANN ◽  
H. MOSSMANN ◽  
G. A. SCHAUB

Blood trypomastigotes of Trypanosoma cruzi were isolated from infected athymic rnu/rnu rats and purified by an improved procedure of DEAE-Sephacel ion-exchange chromatography. Elution into a buffer supplemented with bovine serum albumin avoided column-induced changes on the surface of the parasites. Biotin-labelled bovine serum albumin, fluorescence microscopy, flow cytometry and Western blot analysis revealed a very intense binding of albumin to the parasite. Incubation and washing of cells without protein supplementation did not result in any damage or lysis of parasites but it did cause extensive shedding of cellular and surface proteins into the supernatant which could be prevented by using the protein-supplemented buffer. A decreasing yield of high molecular weight cellular proteins in relation to centrifugal force was a general phenomenon observed in scanning densitometry of SDS gels after isolation in either protein-supplemented buffer or protein-free buffer. The quantity of shed cellular components increased with increasing centrifugal force. In contrast, quantities of high molecular weight, biotin-labelled surface proteins increased with greater centrifugal force, indicating labelling of otherwise inaccessible residues. These data emphasize the importance of protein supplementation of buffers with proteins and of choosing low centrifugation forces (<400 g) during investigations of T. cruzi.


1993 ◽  
Vol 39 (9) ◽  
pp. 861-863 ◽  
Author(s):  
L. J. McElroy ◽  
C. M. Weiss

The mycotoxin patulin is a toxic, carcinogenic, unsaturated lactone produced by a number of molds. Polyclonal antibodies against patulin hemiglutarate were produced. Specific antibodies against patulin alone, however, were not clearly demonstrated. Because of its low molecular weight, patulin required conjugation to bovine serum albumin (BSA) to increase its immunogenicity. Anti-patulin-hemiglutarate-BSA antibody titer and specificity were determined using indirect and indirect competitive ELISA, respectively. Immunoassays would facilitate detection and quantitation of patulin.Key words: patulin, mycotoxin, antibodies.


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