Purification and characterization of thrombin from camel plasma: interaction with camel tick salivary gland thrombin inhibitor
Journal of Genetic Engineering and Biotechnology volume 21, Article number: 7 (2023)
Thrombin is the most important enzyme in the hemostatic process by permitting rapid and localized coagulation in case of tissue damage. Camel thrombin is the natural and proper target enzyme for the previously purified camel tick salivary gland thrombin inhibitor.
In this study, the camel thrombin was purified homogenously in a single affinity chromatographic step on the heparin-agarose affinity column with a specific activity of 3242 NIH units/mg proteins. On SDS-PAGE, the purified camel thrombin contained two forms, 37 kDa α-thrombin and 28 kDa β-thrombin, and the camel prothrombin was visualized as 72 kDa. The camel thrombin Km value was found out as 60 µM of N-(p-Tosyl)-Gly-Pro-Arg-p-nitroanilide acetate and displayed its optimum activity at pH 8.3. The PMSF was the most potent inhibitor of camel thrombin. Camel tick salivary gland thrombin inhibitor has two binding sites on camel thrombin and inhibited it competitively with Ki value of 0.45 µM.
The purified camel thrombin was found to be more susceptible toward the camel tick salivary gland thrombin inhibitor than bovine thrombin.
Blood coagulation is a basic physiological defense mechanism that occurs in all vertebrates to prevent blood loss following vascular injury, and hemostasis is a tightly regulated mechanism that ensures the maintenance of blood flow under physiological conditions. A delicate balance exists between four major components to keep the fluid nature of blood: vascular endothelium, platelets, the coagulation pathway, and fibrinolysis [1,2,3,4,5]. All vertebrates have fine control of their hemostatic system, where any disturbance can cause thrombosis or bleeding events [6,7,8]. In all species, the basic mechanism of clot formation is similar when the endothelium is damaged; a complex sequence of enzymatic reactions occurs that is localized to the site of trauma and involves both activated cells and plasma proteins. Initiation of the reaction sequence is achieved by an expression of a tissue factor on the surface of activated cells that leads to thrombin generation, the most significant enzyme in the process of coagulation. Thrombin is a serine protease of two polypeptides, α- and β-chains, which is centrally implicated in the final step of blood coagulation process [9,10,11,12]. Thrombin converts fibrinogen to fibrin forming the blood clot matrix and exerting a positive feedback regulation for effective promotion of additional thrombin generation to facilitate a rapid thrombus formation [13,14,15,16]. Thrombin is a very important enzyme for the hemostatic process and is produced on request from its circulating zymogen prothrombin in response to different hemostatic activators. The successive and coordinated interactions of coagulation proteins which induce and magnify thrombin formation are controlled by a group of circulating anticoagulants or inhibitory proteins that function to ensuring thrombin generation is limited to areas of vascular injuries, and no excess thrombin is generated [17, 18].
Thrombin is one of the most powerful activators which trigger platelet aggregation ,therefore, the large plurality of anticoagulants aims thrombin or factor Xa in the blood coagulation cascade [20,21,22,23]. Anticoagulants are considered to be fundamental for the succeeded feeding of blood-sucking animals via inhibition of clot formation at feeding sites in mouthparts and gut and by indirect inhibition of platelet aggregation via inhibiting thrombin generation [24,25,26,27]. Thrombin has high substrate specificity through its active site selectivity and via exosite I, a strong positively charged area on its surface, which is involved in thrombin-substrate interactions. Tick molecules inhibit thrombin by targeting exosite I using different mechanisms to prevent its binding to its natural substrates [22, 28]. Therefore, the present study aims at purification and characterization of the camel blood coagulation factor thrombin and the evaluation of the susceptibility of the camel thrombin as the natural and proper target enzyme with the previously purified camel tick salivary gland thrombin inhibitor .
Preparation of the camel plasma
For obtaining the plasma, a mixture of camel blood (900 ml) and 0.11 M sodium citrate solution (100 ml) was centrifuged for 15 min (2700 × g and 4 °C). If plasma was not utilized directly, it was stored at − 40 °C .
Hyalomma dromedarii ticks were brought from camel’s market in Giza governorate. Ticks were dissected for extraction of salivary glands that were washed with 0.9% NaCl saline solution and frozen directly at − 40 °C.
Thrombin (EC 188.8.131.52) from bovine plasma, fibrinogen from bovine plasma, N-(p-Tosyl)-Gly-Pro-Arg-p-nitroanilide acetate salt, ethylene glycol tetraacetic acid (EGTA), hemoglobin from bovine blood, bovine serum albumin (BSA), venom from the snake Oxyuranus scutellatus, and heparin-agarose were purchased from Sigma Chemical Co. Cephalit Kit for APTT, and Kit for PT were bought from bioMẻrieux. All other chemicals were of analytical grade.
Assay of thrombin activity
Chromogenic assay of thrombin was performed in a 96-well microtiter plate at 25 °C. The substrate N-(p-tosyl)-Gly-Pro-Arg-p-nitroanilide acetate salt was dissolved in dH2O at 1.98 mM concentration. The thrombin assay reaction mixture consists of 110 µl: 95 µl 0.05 M Tris-HCI buffer, pH 8.3 containing 0.227 M NaCI and 0.1% BSA, 5 µl enzyme solution, and 10 µl (0.18 mM) substrate. The reaction was started by addition of substrate, and absorbance was recorded every 5 min for 30 min at 405 nm against control lacking enzyme . The clotting activity of thrombin was specified by bovine fibrinogen as substrate (5 mg/ml 0.15 M NaCl). Thrombin activity was expressed in NIH units and derived from a calibration curve for NIH bovine thrombin. The calibration curve was obtained by determination of clotting times of standard thrombin increasing concentrations (0.4–1.8 NIH unit). A total of 0.2 ml of fibrinogen solution is put onto uncoated clotting tubes at 37 °C for 30 s prior to the addition of 0.1 ml of each concentration of thrombin. The clotting times were determined and plotted against the NIH unit of thrombin. Add 0.1 ml of diluted camel thrombin preparation to an uncoated clotting tube, mix with the fibrinogen, and record clotting time. The clotting assay was done in triplicates, and the mean was taken as approximate NIH unit using the constructed calibration curve (Fig. 1a) .
Purification of camel thrombin
Fractionation of plasma
Citrated camel plasma (1 L) was used for thrombin purification, and all successive steps were carried out at 4 °C. A total of 5 mM sodium citrate, 10 mM benzamidine-HCl, and 80 ml 1 M BaCl2 solution were added to 1 L of camel plasma dropwise, slowly stirred for 30 min, and then centrifuged at 3500 × g for 20 min for recovering the barium-adsorbed proteins. The precipitate was washed with 250 ml 0.02 M Tris–HCl buffer, pH 7.5, containing 0.15 M NaCl, 1 mM EGTA, 10 mM BaCl2 and 5 mM benzamidine-HCl utilizing an Omni Mixer to disperse the pellet vigorously, and the precipitate was recovered by centrifugation at 3500 × g for 20 min. The obtained pellet was homogenized in a Teflon-pestled homogenizer using 100 ml 0.2 M EDTA, pH 7.4, and the resulting solution was dialyzed first against 2.5 L 0.02 M Tris–HCl buffer, pH 7.5, 0.15 M NaCl, 1 mM EGTA, and 0.1 M EDTA for 5 h with rapid stirring, and dialysis was continued overnight in the same buffer without EDTA. Dialyzed sample was brought to 35% (NH4)2SO4 saturation, stirred for 20 min at 4 °C, and centrifuged at 8000 × g for 20 min. The filtrate was brought to 70% (NH4)2SO4 saturation, stirred for 40 min, and centrifuged at 12,000 × g for 30 min. The obtained pellet was dissolved in 0.02 M Tris–HCl buffer, pH 7.5 comprising 1 mM EGTA, 1 mM benzamidine-HCL, and 1 mg/ml trypsin inhibitor. This solution was dialyzed extensively with 2.5 L of this buffer and then with other 2.5 L buffer containing 0.1 M NaCl then centrifuged at 12,000 × g for 40 min for removing the precipitated matter .
Activation of prothrombin and heparin-agarose affinity chromatography
CaCl2 solution was put on the described above clarified prothrombin containing solution (10 mM final concentration) followed by addition of Oxyuranus scutellatus snake venom (1:40, w/w). Activation was took place at room temperature for 20 min with quiet stirring and stopped by adding stock EGTA solution to 12 mM final concentration. The final thrombin comprising solution was cooled on ice and then applied onto a heparin-agarose affinity column (8 × 1.8 cm) priorly equilibrated with 0.02 M Tris–HCl buffer pH 7.5, 0.1 M NaCl, and 1 mM EGTA. After sample loading, the column was subjected to an exhaustive washing with the same buffer for removing the nonbound proteins. Bound proteins were eluted with stepwise gradient (0.1–1 M NaCl) in the same buffer and collection of 1 ml fractions with a flow rate of 20 ml/h.
Seven percent native polyacrylamide gel electrophoresis was carried out . Twelve percent SDS-PAGE was performed for determination of subunit molecular weights [34, 35]. Molecular weight markers, phosphorylase b (94 kDa), bovine serum albumin (67 kDa), ovalbumin (43 kDa), carbonic anhydrase (30 kDa), soybean trypsin inhibitor (20.1 kDa), and lactalbumin (14.4 kDa) were used for calibration. Coomassie Brilliant Blue R-250 was used for staining the proteins.
Proteins were estimated through the dye binding assay method by using bovine serum albumin as a standard protein .
Thrombin purification from camel plasma
The activated prothrombin-enriched fraction with snake venom (Oxyuranus scutellatus) was applied directly to heparin-agarose column for affinity chromatography. A typical elution profile (Fig. 1b) showed one thrombin activity peak was eluted with 0.4 M NaCl as detected by the thrombin chromogenic assay and represented by the absorbance at 405 nm. The purification procedure of camel thrombin is summarized in Table 1. The specific activity of the purified camel thrombin was 3242 NIH thrombin unit/mg protein with 10.35-fold and 88.5% recovery.
Electrophoretic analysis of camel thrombin
The purified camel thrombin eluted from heparin-agarose column was analyzed by 7% native PAGE (Fig. 2a) that turned out to be homogenous as shown by one protein band. Purified camel thrombin was also analyzed by 12% SDS PAGE that showed one major protein band of 37 kDa and a minor smaller band of 28 kDa. The camel prothrombin molecular weight was appeared as 72 kDa protein band (Fig. 2b).
Effect of substrate concentration and pH on the camel thrombin activity
Lineweaver–Burk plot for reciprocal of the camel thrombin reaction velocity (1/v) and substrate concentration (1/[S]) was constructed yielding a Km value of 60 µM N-(p-Tosyl)-Gly-Pro-Arg-p-nitroanilide acetate (Fig. 3a). Effect of pH on the activity of camel thrombin was inspected using 0.05 M Tris–HCl buffer, pH (7.2–9.0), and N-(p-Tosyl)-Gly-Pro-Arg-p-nitroanilide acetate as substrate. The thrombin from camel plasma demonstrated its optimum activity at pH 8.3 (Fig. 3b).
Effect of various inhibitors on the camel thrombin activity
Effect of various inhibitors on the activity of camel thrombin was carried out (Table 2). The benzamidine HCl, cysteine, EDTA, EGTA, β-mercaptoethanol, and trypsin inhibitor showed slight inhibition, while PMSF had a strong influence on the purified camel thrombin. A total of 2.5 μM camel tick salivary gland thrombin inhibitor previously purified  inhibited 97% of the purified camel thrombin activity.
Kinetics of camel thrombin inhibition with camel tick salivary gland thrombin inhibitor
Effect of different concentrations (0–3.75 μM) of camel tick salivary gland thrombin inhibitor on the activity of camel thrombin was carried out. A total of 97% maximum inhibition of camel thrombin was achieved by 2.5 μM salivary gland inhibitor (Fig. 4a). On constructing the Hill plot when values of log (Vi/Vmax–Vi) were drew against log [I] of the thrombin inhibitor, a direct line was acquired with a slope of 1.8 (Fig. 4b). Lineweaver–Burk plot indicated that the inhibition of camel thrombin with the salivary gland inhibitor is competitive (Fig. 4c) with a Ki value 0.45 μM (Fig. 4d).
The main role of thrombin is to catalyze the transformation of fibrinogen to fibrin necessary for thrombus generation. Thrombin activates factor XIII to cross with fibrin for stabilizing, promoting, and amplifying the clot formation via activation of other clotting factors [7, 37]. Thrombin also plays a key role in other physiological processes as it has been used clinically as a hemostatic agent to stanch oozing hemorrhages in the field of surgery and effective in stopping bleeding on local wounds and in the gastrointestinal organs [38, 39]. It is also utilized as a constituent in surgical binding factors in human surgeries and in the meat industry [10, 12].
In the present study, camel prothrombin was efficaciously fractionated from other coagulation agents via utilizing barium citrate adsorption. The dialysis of the barium-adsorbed plasma proteins mixture in buffer containing EDTA led to the releasing of proteins from this adsorbed complex, and this is the most critical step in the recovery of prothrombin from plasma. The camel thrombin was prepared with a single affinity chromatographic step on heparin-agarose column (Fig. 1b) with a specific activity of 3242 NIH units/mg proteins, 10.35-fold, and 88.5% recovery (Table 1). The prepared camel thrombin was found to be homogenous as proved by the 7% native PAGE (Fig. 2a). Thrombin was purified from human plasma with a specific activity of 4000 NIH units/mg protein  and 2400 IU/mg protein , from bovine plasma 4018 NIH units/mg , and from salmon blood 1000 units/mg protein .
In this study, the purified camel thrombin contained one major band with apparent molecular weight of 37 kDa in consistence with the size prospected for α-thrombin and a minor smaller protein of 28 kDa in consistence with the size prospected for β-thrombin. Molecular weight of camel prothrombin was approximately appeared as 72 kDa (Fig. 2a). On comparison of the reported thrombin molecular weights, the molecular weight of bovine prothrombin was 72 kDa, the activation of which resulted in two single-chain molecules of 39 kDA and 24 kDa . SDS-PAGE showed the bovine thrombin as one major band of 35 kDa and a minor protein suggested being β-thrombin . The human prothrombin and thrombin were reported to be 70 and 34.8 kDa  and 72 kDa and 37 kDa . Three forms of human thrombin were visualized as follows: 37 kDa α-thrombin, 27 kDa β-thrombin, and 13 kDa γ-thrombin . The salmon thrombin molecular weight was 37 kDa .
In this study, the Km value of the purified camel thrombin was 60 µM of N-(p-Tosyl)-Gly-Pro-Arg-p-nitroanilide acetate (Fig. 3a) indicating the high affinity of the purified camel thrombin toward N-p-Tosyl-Gly-Pro-Arg-p-nitroanilide acetate. The purified camel thrombin exhibited its maximum activity at pH 8.3 (Fig. 3b). In consistent with this result, salmon thrombin exhibited its maximum activity at pH 8.5, while human thrombin exhibited its maximum activity at pH 8.0 . The purified camel thrombin was partially inhibited with benzamidine HCl and EGTA. It was slightly inhibited with cysteine and EDTA which indicated that it is neither cysteinyl proteinase nor a metalloenzyme. Inhibition of camel thrombin by β-mercaptoethanol denotes the existence of a disulfide bond in the thrombin molecule and trypsin inhibitor denoting it as a serine protease. The serine protease inhibitor PMSF was found to be the most powerful inhibitor of camel thrombin indicating that the enzyme active site contains a serine residue (Table 2). The titration curve of the salivary gland thrombin inhibitor toward the camel thrombin activity (Fig. 4a) emphasized inhibition of camel thrombin with the maximum inhibition (97%) was reached by 2.5 μM of the inhibitor, while 3.75 μM of this inhibitor inhibited 82% of bovine thrombin . Two binding sites are derived for the salivary gland inhibitor on camel thrombin because the slope of the Hill plot was found as 1.8 (Fig. 4b). Existence of the salivary gland thrombin inhibitor did not alter the value of Vmax and increases the Km value denoting a competitive inhibition of camel thrombin by camel tick salivary gland thrombin inhibitor (Fig. 4c) with Ki value of 0.45 μM (Fig. 4d). The salivary gland thrombin inhibitor had only one binding site on bovine thrombin and Ki value of 0.55 μM  confirming the higher susceptibility of the camel thrombin as the proper and natural target enzyme to the inhibitor than the bovine thrombin. A competitive inhibition of thrombin was achieved by americanin, savignin and NTI-2 [42,43,44], and a noncompetitive inhibition by NTI-1 . Ki values of dipetarudin, a chimeric thrombin inhibitor from the assassin bug Dipetalogaster maximus, have been reported to be 446 fM  and 399 ± 83 fM of dipetarudin fron Pichia pastoros .
In conclusion, this study provides simple, reproducible, and appropriate method for purification of thrombin from camel plasma which is very valuable as hemostatic factor. The purified camel thrombin was found more susceptible toward the camel tick salivary gland thrombin inhibitor than bovine thrombin. This thrombin inhibitor can be applicable in two major directions: (1) in tick control, since antibodies directed to this inhibitor may block the successful feeding of ticks, and (2) therapeutic purposes where the potency and specificity of this thrombin inhibitor indicate that it may be effective in the treatment of thrombosis.
Availability of data and materials
All data generated or analyzed during this study are included in this published article and available upon request from the corresponding author.
Bovine serum albumin
Polyacrylamide gel electrophoresis
Ethylene glycol tetraacetic acid
Allford SL, Machin SJ (2007) Haemostasis Surg 25(6):241–244
Lewis I, Lee S (2007) Physiology of haemopoesis Surg 25(1):3–9
Shannon M (2007) Anticoagulation Surg 25(4):150–154
Sharma R, Waller AP, Agrawal S, Wolfgang KJ, Luu H, Shahzad K, Isermann B, Smoyer WE, Nieman MT, Kerlin BA (2017) Thrombin-induced podocyte injury is protease-activated receptor dependent. Am Soc Nephrol 28:2618–2630
Shirodaria CC, Channon KM (2007) Nitric oxide and vascular disease Surg 25(4):145–149
Appleby RD, Olds RJ (1997) The inherited basis of venous thrombosis. Pathol 29:341–347
Mack H, Baucke D, Hornberger W, Lange UEW, Seitzb W, Hoffken HW (2006) Orally active thrombin inhibitors. Part 1: Optimization of the P1-moiety. Bioorg Med Chem Lett 16:2641–2647
Mihara K, Ramachandran R, Saifeddine M, Hansen KK, Renaux B, Polley D, Gibson S, Vanderboor C, Hollenberg MD (2016) Thrombin-mediated direct activation of proteinase-activated receptor-2: another target for thrombin signaling. Mol Pharmacol 89:606–614
Licari LG, Kovacic JP (2009) Thrombin physiology and pathophysiology. J Vet Emerg Crit Care 19(1):11–22
Michaud SE, Wang LZ, Kord N, Buckib R, Randhaw PK, Pastoreb JJ, Falet H, Hoffmeister K, Kuuse R, Uiboc R, Herodd J, Sawyerd E, Janmeya PA (2002) Purification of salmon thrombin and its potential as an alternative to mammalian thrombins in fibrin sealants. Thromb Res 107:245–254
Tripodi A (2016) Thrombin generation assay and its application in the clinical laboratory. Clin Chem 62(5):699–707
Wang LZ, Gorlin J, Michaud SE, Janmey PA, Goddeau RP, Kuuse R (2000) Purification of salmon clotting factors and their use as tissue sealants. Thromb Res 100:537–548
Anand M, Rajagopal K, Rajagopal R (2008) A model for the formation, growth, and lysis of clots in quiescent plasma. A comparison between the effects of antithrombin III deficiency and protein C deficiency. J Theoret Biol 253(4):725–738
Colman RW (2001) Contact activation pathway: Inflammatory, fibrinolytic, anticoagulant, antiadhesive and antiangiogenic activities. In: Colman RW, Hirsh J, Marder VJ, Clowes AW, George JN (eds) Hemostasis and Thrombosis: Basic Principles and Clinical Practice. Lippincott Williams and Wilkins, Philadelphia, pp 103–121
Dahlback B (2000) Blood coagulation. Lancet 355:1627–1632
Gentry PA (2004) Comparative aspects of blood coagulation. Veterin J 168:238–251
de Oliveira FM, de Carvalho MVH, Marchi E, Pinto CAL (2016) Collagen, fibrinogen and thrombin biological addesive is effective in treating experimental liver injuries. Rev Col Bras Cir 43(4):254–261
Gentry PA, Downie HG (1993) Blood coagulation and homeostasis. "Duke s’ Physiology of domestic animals" 11. Cornell University Press, Ithaca, pp 49–63
Tapparelli C, Metternich R, Ehrhardt C, Cook N (1993) Synthetic low-molecular weight thrombin inhibitors: molecular design and pharmacological profile. Trend Pharmacol Sci 14:366–376
Ibrahim MA, Masoud HMM (2018) Thrombin inhibitor from the salivary gland of the camel tick Hyalomma dromedarii. Exp Appl Acarol 74:85–97
Iyer JK, Koh CY, Kazimirova M, Roller L, Jobichen C, Swaminathan K, Mizuguchi J, Iwanaga S, Nuttall PA, Chan MY, Kini RM (2017) Avathrin: a novel thrombin inhibitor derived from a multicopy precursor in the salivary glands of the ixodid tick. Amblyomma variegatum FASEB J 31(7):2981–2995
Jablonka W, Kotsyfakis M, Mizurini DM, Monteiro RQ, Lukszo J, Drake SK, Ribeiro JMC, Andersen KF (2015) Identification and mechanistic analysis of a novel tick-derived inhibitor of thrombin. PLoS ONE 10(8):e0133991
Narasimhan S, Perez O, Mootien S, DePonte K, Koski RA, Fikrig E, Ledizet M (2013) Characterization of ixophilin, a thrombin inhibitor from the gut of ixodes scapularis. PLoS ONE 8(7):e68012
Brahma RJ, Blanchet G, Kaur S, Kini RM, Doley R (2017) Expression and characterization of haemathrins, madanin-like thrombin inhibitors, isolated from the salivary gland of tick Haemaphysalis bispinosa (Acari: Ixodidae). Thromb res 152:20–29
Mans BJ, Neitz AW (2004) Adaptation of ticks to a blood-feeding environment: evolution from a functional perspective. Ins Bioch Mol Biol 34:1–17
Ribeiro JM, Francischetti IM (2003) Role of arthropod saliva in blood feeding: sialome and post-sialome perspectives. Ann Rev Entomol 48:73–88
Thompson RE, Liu X, Ripoll-Rozada J, Alonso-García N, Parker BL, Pereira PJB, Payne RJ (2017) Tyrosine sulfation modulates activity of tick-derived thrombin inhibitors. Nature Chem 9:909–917
Koh CY, Shih N, Yip CYC, Li AWL, Chen W, Amran FS, Leong EJE, Iyer JK, Croft G, Bin Mazlan MI, Chee Y, Yap E, Monroe DM, Hoffman M, RCB, de Kleijn DPV, Verma V, Gupta A, Chaudhary VK, Richards AM, Kini RM, Chan MY, (2021) Efficacy and safety of next-generation tick transcriptome-derived direct thrombin inhibitors. Nat Commun 12:6912
Joubert AM, Crause JC, Gaspar AR, Clarke FC, Spickett AM, Neitz AW (1995) Isolation and characterization of an anticoagulant present in the salivary glands of the bont-legged tick, Hyalomma truncatum. Exp Appl Acarol 19:79–92
Gaspar ARMD, Crause JC, Neitz AWH (1995) Identification of anticoagulant activities in the salivary glands of the soft tick, Ornithodoros savignyi. Exp Appl Acarol 19:117–126
Ding Z, Xu Y (1995) A rapid simplified purification of bovine thrombin. Prep Biochem 25:21–28
Ngai PK, Chang JY (1991) A novel one-step purification of human α-thrombin after direct activation of crude prothrombin enriched from plasma. Biochem J 280:805–808
Smith I (1969) Acrylamide gel disc electrophoresis. In: Smith I (ed) Electrophoretic techniques. Academic Press, New York, pp 365–515
Laemmli UK (1970) Cleavage of structural proteins during the assembly of the head of Bacteriophage T4. Nat 227:680–685
Weber K, Osborn M (1969) The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis. J Biol Chem 244:4406–4412
Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72:248–254
Barkhordari A, Behzad-Behbahani A, Jajarmi V, Bandehpour M, RafIei-Dehbidi G, Safari F, Mahboudi F (2020) Kazemi1 B (2020) Direct cloning, expression and purifcation of human activated thrombin in prokaryotic system and CD analysis report of produced thrombin: molecular characterization of recombinant thrombin. Int J Pept Res Therap 26:2661–2673
Bode W, Turk D, Karshikov A (1992) The refined 1.9-A X-ray crystal structure of D-Phe-Pro-Arg chloromethylketone-inhibited human alpha-thrombin: Structure analysis, overall structure, electrostatic properties, detailed active-site geometry, and structure-function relationships. Prot Sci 1(4):426–471
Kaetsu H, Mizuguchi J, Hamamoto T, Kamimura K, Yoshida Y, Nakagaki T, Ogata Y, Miyamoto S, Funatsu A (1998) Large-scale preparation of human thrombin: polyethylene glycol potentiates the factor Xa-mediated activation of prothrombin. Thromb Res 90:101–109
Aizawa P, Winge S, Karlsson G (2008) Large-scale preparation of thrombin from human plasma. Thromb Res 122(4):560–567
Mann KG, Heldebrant CM, Fass DN (1971) Multiple active forms of thrombin. Mechanism of production from prothrombin. J Biol Chem 246:6106–6114
Ibrahim MA, Ghazy AM, Maharem T, Khalil M (2001) Isolation and properties of two forms of thrombin inhibitor from the nymphs of the camel tick Hyalomma dromedarii (Acari: Ixodidae). Exp Appl Acarol 25:675–698
Nienaber J, Gaspar AR, Neitz AW (1999) Savignin, a potent thrombin inhibitor isolated from the salivary glands of the tick Ornithodoros savignyi (Acari: Argasidae). Exp Parasitol 93:82–91
Zhu K, Bowman AS, Brigham DL, Essenberg RC, Dillwith JW, Sauer JR (1997) Isolation and characterization of americanin, a specific inhibitor of thrombin, from the salivary glands of the lone star tick Amblyomma americanum (L.). Exp Parasit 87:30–38
Lopez M, Mende K, Steinmetzer T, Nowak G (2003) Cloning, purification and biochemical characterization of dipetarudin, a new chimeric thrombin inhibitor. J Chromat B 786:73–80
Lopez M, Koehler A, Nowak G (2007) High level secretion of dipetarudin, a chimeric thrombin inhibitor by Pichia pastoris. Prot Expr Pur 52:8–13
This study was supported and funded by National Research Centre, Egypt.
This study was funded by the National Research Centre, Egypt.
Ethics approval and consent to participate
Consent for publication
The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Ibrahim, M.A., Masoud, H.M.M. Purification and characterization of thrombin from camel plasma: interaction with camel tick salivary gland thrombin inhibitor. J Genet Eng Biotechnol 21, 7 (2023). https://doi.org/10.1186/s43141-023-00464-2