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Binding of prothrombin to chyle chylomicrons: effects of temperatuure and calcium ions, and role of surface phospholipids.

Xu, Ning LU ; Öhlin, Ann-Kristin LU ; Zhou, Li LU and Nilsson, Åke LU (1995) In Thrombosis Research 80(1). p.35-46
Abstract (Swedish)
The ability of chyle chylomicrons to bind prothrombin has been studied. Rat chyle chylomicrons were incubated with human 125I-prothrombin and binding was examined by separating the chylomicrons from free 125-I-prothrombin by density-gradient ultracentrifugation, and by gel filtration on Sepharose CL-2B. A significant binding of prothrombin to chyle chylomicrons occurred. The complex formation was calcium dependent, and decreased markedly when the temperature was lowered from 37 degrees C to 20 degrees C and when PH was raised above 8. The time course for the binding at 37 degrees C in presence of 2 mmol/L CaCl2 exhibited an initial lag phase at about 10 minutes. Thereafter most of the binding occurred within 30 minutes. Bound prothrombin... (More)
The ability of chyle chylomicrons to bind prothrombin has been studied. Rat chyle chylomicrons were incubated with human 125I-prothrombin and binding was examined by separating the chylomicrons from free 125-I-prothrombin by density-gradient ultracentrifugation, and by gel filtration on Sepharose CL-2B. A significant binding of prothrombin to chyle chylomicrons occurred. The complex formation was calcium dependent, and decreased markedly when the temperature was lowered from 37 degrees C to 20 degrees C and when PH was raised above 8. The time course for the binding at 37 degrees C in presence of 2 mmol/L CaCl2 exhibited an initial lag phase at about 10 minutes. Thereafter most of the binding occurred within 30 minutes. Bound prothrombin could not be removed from chyle chylomicrons by treatment with EDTA, suggesting that this binding is not a simple Ca2+ dependent association between prothrombin and chyle chylomicrons. Inclusion of 1% purified human serum albumin caused a 50% decrease in binding, half of which was reversed by increasing the Ca2+ ion concentration. Addition of pancreatic phospholipase A2 (PLA2) in doses sufficient to hydrolyze more than 95% of the phosphatidylethanolamine (PE) and 37% of the phosphatidylcholine (PC) decreased the binding by 50%. Doses of PLA2 that hydrolyze more than 95% of the phosphatidylethanolamine (PE) and 37% of the phosphatidylcholine (PC) decreased the binding by 50%. Doses of PLA2 that hydrolyzed 60-80% of (PE and 4-10% of the PC decreased the binding by only 7-15%. It is suggested that the binding of prothrombin to chyle chylomicrons is in part mediated by negatively charged phospholipids of the chylomicron surface, although a specific role of the PE could not be demonstrated. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Thrombosis Research
volume
80
issue
1
pages
35 - 46
publisher
Elsevier Ltd
external identifiers
  • pmid:8578536
ISSN
1879-2472
DOI
10.1016/0049-3848(95)00148-K
language
English
LU publication?
no
id
739fcc6b-cfa0-4f02-b948-9661e0451cb2
date added to LUP
2019-06-20 13:59:53
date last changed
2020-01-01 04:02:01
@article{739fcc6b-cfa0-4f02-b948-9661e0451cb2,
  abstract     = {The ability of chyle chylomicrons to bind prothrombin has been studied. Rat chyle chylomicrons were incubated with human 125I-prothrombin and binding was examined by separating the chylomicrons from free 125-I-prothrombin by density-gradient ultracentrifugation, and by gel filtration on Sepharose CL-2B. A significant binding of prothrombin to chyle chylomicrons occurred. The complex formation was calcium dependent, and decreased markedly when the temperature was lowered from 37 degrees C to 20 degrees C and when PH was raised above 8. The time course for the binding at 37 degrees C in presence of 2 mmol/L CaCl2 exhibited an initial lag phase at about 10 minutes. Thereafter most of the binding occurred within 30 minutes. Bound prothrombin could not be removed from chyle chylomicrons by treatment with EDTA, suggesting that this binding is not a simple Ca2+ dependent association between prothrombin and chyle chylomicrons. Inclusion of 1% purified human serum albumin caused a 50% decrease in binding, half of which was reversed by increasing the Ca2+ ion concentration. Addition of pancreatic phospholipase A2 (PLA2) in doses sufficient to hydrolyze more than 95% of the phosphatidylethanolamine (PE) and 37% of the phosphatidylcholine (PC) decreased the binding by 50%. Doses of PLA2 that hydrolyze more than 95% of the phosphatidylethanolamine (PE) and 37% of the phosphatidylcholine (PC) decreased the binding by 50%. Doses of PLA2 that hydrolyzed 60-80% of (PE and 4-10% of the PC decreased the binding by only 7-15%. It is suggested that the binding of prothrombin to chyle chylomicrons is in part mediated by negatively charged phospholipids of the chylomicron surface, although a specific role of the PE could not be demonstrated.},
  author       = {Xu, Ning and Öhlin, Ann-Kristin and Zhou, Li and Nilsson, Åke},
  issn         = {1879-2472},
  language     = {eng},
  month        = {10},
  number       = {1},
  pages        = {35--46},
  publisher    = {Elsevier Ltd},
  series       = {Thrombosis Research},
  title        = {Binding of prothrombin to chyle chylomicrons: effects of temperatuure and calcium ions, and role of surface phospholipids.},
  url          = {http://dx.doi.org/10.1016/0049-3848(95)00148-K},
  doi          = {10.1016/0049-3848(95)00148-K},
  volume       = {80},
  year         = {1995},
}