fibrinopeptide-b and Hemorrhage

From the snake venom of Agkistrodon acutus, two proteases, acuthrombin-A and acuthrombin-C, were isolated and purified to homogeneity. They can cleave the human fibrinogen to release the fibrinopeptide A and fibrinopeptide B with specific activity of 120 and 370 NIH units/mg, respectively; the fibrinogen-clotting activity can be inhibited distinctly by PMSF or DFP or EDTA, but not by heparin. The two proteases show also arginine-esterase activity hydrolyzing some synthetic substrates such as TAME and BAEE. Additionally, they are glycoproteins with an average content of 2.4% (acuthrombin-A) and 2.1% (acuthrombin-C) neutral carbohydrates, respectively. Acuthrombin-A has a MW of 13,900 as estimated by SDS-PAGE under reduced or nonreduced conditions and 28,000 as determined by gel filtration. For acuthrombin-C, there were two protein bands corresponding to MW of 13,900 and 14,800 on SDS-PAGE with different darkness under reduced or nonreduced conditions, while its MW was estimated to be 69,000 by gel filtration. The isoelectric points were 7.5 for acuthrombin-A and 5.0 for acuthrombin-C by isoelectric focusing. Neither acuthrombin-A nor acuthrombin-C has haemorrhagic or lethal activity. Acuthrombin-A has also a small amount of activity to activate the Factor XIII.

Topics: Agkistrodon; Animals; Blood Coagulation; Chromatography, Gel; Endopeptidases; Esterases; Factor XIII; Fibrinogen; Fibrinopeptide A; Fibrinopeptide B; Hemorrhage; Humans; Hydrolysis; Mice; Oxidation-Reduction; Peptide Hydrolases; Rabbits; Snake Venoms; Thrombin

Proteolysis of coagulation factors and inhibitors resulting in haemorrhage can be mediated by elastase. Indirect signs of this are elevated levels of elastase complexed to its inhibitor in plasma, alpha 1-antitrypsin (E alpha 1-AT). We have measured intracellular elastase activity in leukaemic cells from 60 patients with acute leukaemia. Elastase activity was detected in 92% of the patients with acute nonlymphoblastic leukaemia (ANL), no activity was found in the patients with acute lymphoblastic leukaemia (ALL). High levels were found in cells from patients with promyelocytic leukaemia. Moderate to high total circulating blast elastase activity was measured in 70% of the ANL patients with haemorrhage compared with 36% of the patients without bleeding complications (p < 0.05). The available intracellular elastase activity was correlated to the level of E alpha 1-AT (rs = 0.42, p < 0.01) but not to the elastase specific split product of fibrinogen, B beta 30-43. In complete remission the levels of E alpha 1-AT were normalized. Intracellular elastase activity might be a useful supplement to differentiate ANL and ALL.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; alpha 1-Antitrypsin; Biomarkers, Tumor; DNA; Female; Fibrin Fibrinogen Degradation Products; Fibrinopeptide B; Hemorrhage; Humans; Leukemia, Myeloid, Acute; Male; Middle Aged; Pancreatic Elastase; Peptide Fragments; Peptides; Platelet Count; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Sepsis; Tissue Polypeptide Antigen

Topics: Disseminated Intravascular Coagulation; Electrophoresis, Polyacrylamide Gel; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinopeptide A; Fibrinopeptide B; Hemorrhage; Humans; Models, Chemical; Molecular Weight; Thrombosis