PMID: 11330346May 2, 2001Paper

The effect of calcium (II) on the binding of anticoagulation factor I with activated coagulation factor X

Journal of Protein Chemistry
X XuY Xie

Abstract

Anticoagulation factor I (ACF I) from the venom of Agkistrodon acutus forms a 1:1 complex with activated coagulation factor X (FXa) in a Ca2+-dependent fashion and thereby prolongs the clotting time. In the present study, the dependence of the binding of ACF I with FXa on the concentration of Ca2+ ions was quantitatively analyzed by HPLC, and the result showed that the maximal binding of ACF I to FXa occurred at concentration of Ca2+ ions of about 1 mM. The binding of Ca2+ ions to ACF I was investigated by equilibrium dialysis and two Ca2+-binding sites with different affinities were identified. At pH 7.6, the apparent association constants K1 and K2 for these two sites were (1.8 +/- 0.5) x 10(5) and (2.7 +/- 0.6) x 10(4) M(-1) (mean +/- SE, n = 4), respectively. It was evident from the observation of Ca2+-induced changes in the intrinsic fluorescence of ACF I that ACF I underwent a conformational change upon binding of Ca2+ ions. The occupation of both Ca2+-binding sites in ACF I required a concentration of Ca2+ ions of about 1 mM, which is equal to the effective concentration of Ca2+ ions required both for maximal binding of ACF I to FXa and for the maximal enhancement of emission fluorescence of ACF I. It could be deduced fr...Continue Reading

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.