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Lee JH, Reier J, Heffner KM, Barton C, Spencer D, Schmelzer AE, Venkat R. Production and characterization of active recombinant human factor II with consistent sialylation. Biotechnol Bioeng 2017; 114:1991-2000. [DOI: 10.1002/bit.26317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 04/04/2017] [Accepted: 04/17/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Jeong H. Lee
- Biopharmaceutical Development; MedImmune; 1 MedImmune Way Gaithersburg 20878 Maryland
| | - Jason Reier
- Biopharmaceutical Development; MedImmune; 1 MedImmune Way Gaithersburg 20878 Maryland
| | - Kelley M. Heffner
- Department of Chemical and Biomolecular Engineering; Johns Hopkins University; Baltimore Maryland
| | | | - David Spencer
- Ipsen Biopharm Limited; Wrexham Industrial Estate, Wrexham United Kingdom
| | - Albert E. Schmelzer
- Biopharmaceutical Development; MedImmune; 1 MedImmune Way Gaithersburg 20878 Maryland
| | - Raghavan Venkat
- Biopharmaceutical Development; MedImmune; 1 MedImmune Way Gaithersburg 20878 Maryland
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Kinukawa H, Shirakawa T, Yoshimura T. Epitope characterization of an anti-PIVKA-II antibody and evaluation of a fully automated chemiluminescent immunoassay for PIVKA-II. Clin Biochem 2015; 48:1120-5. [DOI: 10.1016/j.clinbiochem.2015.08.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 08/16/2015] [Indexed: 11/17/2022]
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3
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Development and evaluation of analytical performance of a fully automated chemiluminescent immunoassay for protein induced by vitamin K absence or antagonist II. Clin Biochem 2015. [PMID: 26210849 DOI: 10.1016/j.clinbiochem.2015.07.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVES Protein induced by vitamin K absence or antagonist II (PIVKA-II), an abnormal form of prothrombin, has been used as an aid in the diagnosis of hepatocellular cancer (HCC) as a tumor marker. We developed a fully automated quantitative immunoassay for PIVKA-II on the ARCHITECT® i systems. The aim of this study was to evaluate the analytical performance of this assay. DESIGN AND METHOD Assay imprecision, sensitivity, dilution linearity, high dose hook effect, sample type equivalency, assay interferences of potential interfering materials and correlation with Picolumi PIVKA-II (Eidia, Tokyo, Japan) were evaluated. RESULTS The percentage coefficient of variation (%CV) of total imprecision ranged from 2.8% to 5.4% with 10 levels of samples. The limit of blank (LoB), limit of detection (LoD), and limit of quantitation (LoQ) were less than 0.63 mAU/mL, 1.62 mAU/mL, and 8.25 mAU/mL, respectively. Linearity up to 30,000 mAU/mL, no high dose hook effect, no difference among sample types and no interference of common drugs and endogenous substances were observed. Correlation study with the Picolumi PIVKA-II gave a correlation coefficient of 0.93 and a regression slope of 1.07. CONCLUSIONS The results demonstrate that the fully automated prototype ARCHITECT PIVKA-II assay is an accurate, highly sensitive and precise assay for the measurement of PIVKA-II levels in human sera and plasmas.
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Vadivel K, Agah S, Messer AS, Cascio D, Bajaj MS, Krishnaswamy S, Esmon CT, Padmanabhan K, Bajaj SP. Structural and functional studies of γ-carboxyglutamic acid domains of factor VIIa and activated Protein C: role of magnesium at physiological calcium. J Mol Biol 2013; 425:1961-1981. [PMID: 23454357 PMCID: PMC4017951 DOI: 10.1016/j.jmb.2013.02.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 02/10/2013] [Accepted: 02/14/2013] [Indexed: 11/28/2022]
Abstract
Crystal structures of factor (F) VIIa/soluble tissue factor (TF), obtained under high Mg(2+) (50mM Mg(2+)/5mM Ca(2+)), have three of seven Ca(2+) sites in the γ-carboxyglutamic acid (Gla) domain replaced by Mg(2+) at positions 1, 4, and 7. We now report structures under low Mg(2+) (2.5mM Mg(2+)/5mM Ca(2+)) as well as under high Ca(2+) (5mM Mg(2+)/45 mM Ca(2+)). Under low Mg(2+), four Ca(2+) and three Mg(2+) occupy the same positions as in high-Mg(2+) structures. Conversely, under low Mg(2+), reexamination of the structure of Gla domain of activated Protein C (APC) complexed with soluble endothelial Protein C receptor (sEPCR) has position 4 occupied by Ca(2+) and positions 1 and 7 by Mg(2+). Nonetheless, in direct binding experiments, Mg(2+) replaced three Ca(2+) sites in the unliganded Protein C or APC. Further, the high-Ca(2+) condition was necessary to replace Mg4 in the FVIIa/soluble TF structure. In biological studies, Mg(2+) enhanced phospholipid binding to FVIIa and APC at physiological Ca(2+). Additionally, Mg(2+) potentiated phospholipid-dependent activations of FIX and FX by FVIIa/TF and inactivation of activated factor V by APC. Since APC and FVIIa bind to sEPCR involving similar interactions, we conclude that under the low-Mg(2+) condition, sEPCR binding to APC-Gla (or FVIIa-Gla) replaces Mg4 by Ca4 with an attendant conformational change in the Gla domain ω-loop. Moreover, since phospholipid and sEPCR bind to FVIIa or APC via the ω-loop, we predict that phospholipid binding also induces the functional Ca4 conformation in this loop. Cumulatively, the data illustrate that Mg(2+) and Ca(2+) act in concert to promote coagulation and anticoagulation.
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Affiliation(s)
- Kanagasabai Vadivel
- UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
| | - Sayeh Agah
- UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
| | - Amanda S Messer
- UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA
| | - Duilio Cascio
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Madhu S Bajaj
- Division of Pulmonology and Critical Care, Department of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Sriram Krishnaswamy
- Department of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Charles T Esmon
- Oklahoma Medical Research Foundation, Howard Hughes Medical Institute, Oklahoma City, OK 73104, USA
| | - Kaillathe Padmanabhan
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - S Paul Bajaj
- UCLA/Orthopaedic Hospital Department of Orthopaedic Surgery, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.
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Takeji S, Hirooka M, Koizumi Y, Tokumoto Y, Abe M, Ikeda Y, Nadano S, Hiasa Y, Onji M. Des-gamma-carboxy prothrombin identified by P-11 and P-16 antibodies reflects prognosis for patients with hepatocellular carcinoma. J Gastroenterol Hepatol 2013; 28:671-7. [PMID: 23215762 DOI: 10.1111/jgh.12076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/24/2012] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND AIMS Serum des-γ-carboxy prothrombin (DCP) is an established tumor marker in patients with hepatocellular carcinoma (HCC), which can be identified by using MU-3 antibody. The MU-3 antibody mainly reacts with the 9-10 glutamic acid residues of DCP (conventional DCP). Since other variants of DCP with fewer glutamic acid residues can be detected using P-11 and P-16 antibodies (code name: NX-PVKA), we examined the clinical characteristics associated with NX-PVKA, and whether NX-PVKA is a useful measure in HCC patients. METHODS Participants comprised 197 HCC patients admitted to our hospital between 2001 and 2010. NX-PVKA, conventional DCP, alpha-fetoprotein, and L3 fraction of alpha-fetoprotein were measured prior to initiation of HCC treatment. RESULTS Of the tumor markers assessed, NX-PVKA was the only significant predictor of prognosis (hazard ratio, 81.32; P < 0.0001). Patients with NX-PVKA level ≥ 100 mAU/mL showed significantly lower survival rates (P < 0.0001). NX-PVKA level was also significantly associated with platelet count, prothrombin time, C-reactive protein, sex, maximum tumor size, number of nodules, and portal venous invasion by HCC. Finally, using NX-PVKA level and other clinical parameters, we established a prognostic model to estimate patient survival time. CONCLUSIONS NX-PVKA offers the best marker of tumor prognosis among HCC patients, and is strongly associated with tumor factors and hepatic functional reserve. NX-PVKA could be useful for clinical evaluation of tumor severity, as well as the estimated duration of survival among patients with HCC.
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Affiliation(s)
- Satoru Takeji
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
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Toyoda H, Kumada T, Osaki Y, Tada T, Kaneoka Y, Maeda A. Novel method to measure serum levels of des-gamma-carboxy prothrombin for hepatocellular carcinoma in patients taking warfarin: a preliminary report. Cancer Sci 2012; 103:921-5. [PMID: 22320249 DOI: 10.1111/j.1349-7006.2012.02232.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 01/30/2012] [Accepted: 01/31/2012] [Indexed: 12/31/2022] Open
Abstract
Des-gamma-carboxy prothrombin (DCP) is a useful tumor marker for hepatocellular carcinoma (HCC), but its utility is limited in patients taking vitamin K antagonists. We evaluated the NX-DCP ratio, a newly developed method to measure serum DCP, for its ability to identify DCP elevation induced by HCC in this patient subpopulation. Conventional DCP measurements and the NX-DCP ratio were compared in patients with and without HCC, all of whom were taking the vitamin K antagonist warfarin. We found no differences in conventional DCP measurements between patients with and without HCC due to warfarin treatment. In contrast, the NX-DCP ratio was significantly higher in patients with HCC; the NX-DCP ratio in all patients without HCC was <1.50. When the cut-off was fixed at 1.50, sensitivity and specificity for HCC diagnosis were 60.0% and 100.0%, respectively, which are comparable to those of conventional DCP measurements in patients not taking warfarin. The novel NX-DCP ratio identifies patients on warfarin with elevated DCP due to HCC and is useful as a tumor marker for HCC in this patient subpopulation.
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Affiliation(s)
- Hidenori Toyoda
- Department of Gastroenterology, Ogaki Municipal Hospital, Ogaki, Japan.
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8
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Yamaguchi I, Nakamura K, Kitano H, Masuda Y, Kanke F, Kobatake S, Satomura S. Development of des-γ-carboxy prothrombin (DCP) measuring reagent using the LiBASys clinical analyzer. ACTA ACUST UNITED AC 2008; 46:411-6. [DOI: 10.1515/cclm.2008.078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Black RS, Adams GM, Jorgenson JW, Hiskey RG. Counting Integral Numbers of γ-Carboxyglutamic Acids Per Peptide Chain Using Capillary Electrophoresis. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079708005560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Roderick S. Black
- a Department of Chemistry , University of North Carolina at Chapel Hill , CB #3290, Venable Hall, Chapel Hill, North Carolina, 27599
| | - George M. Adams
- a Department of Chemistry , University of North Carolina at Chapel Hill , CB #3290, Venable Hall, Chapel Hill, North Carolina, 27599
| | - James W. Jorgenson
- a Department of Chemistry , University of North Carolina at Chapel Hill , CB #3290, Venable Hall, Chapel Hill, North Carolina, 27599
| | - Richard G. Hiskey
- a Department of Chemistry , University of North Carolina at Chapel Hill , CB #3290, Venable Hall, Chapel Hill, North Carolina, 27599
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Liu J, Wang T, Chen J, Wang S, Ye Z. Decreased inhibitory activity of prothrombin to calcium oxalate crystallization by specific chemical modification of its gamma-carboxyglutamic acid residues. Urology 2006; 67:201-3. [PMID: 16413375 DOI: 10.1016/j.urology.2005.07.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2004] [Accepted: 07/22/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES To investigate the inhibitory role of gamma (gamma)-carboxyglutamic acid (Gla) in the Gla domain of urinary prothrombin in the formation of calcium oxalate crystals. METHODS Morpholine and formaldehyde at different concentrations were added to the solution of prothrombin to cause the conversion of Gla to gamma-methyleneglutamic acid (MGlu). The extent of the modification was controlled by the relative amount of modification reagents to prothrombin. The 100-fold molar excess of modification reagents to prothrombin produced the prothrombin molecule containing 2gamma-MGlu residues, and the 10,000-fold molar excess produced the molecule containing 8gamma-MGlu residues. The inhibitory activities of prothrombin and modified prothrombin to calcium oxalate crystallization were evaluated by the seeded crystallization technique. RESULTS The inhibitory index of Gla prothrombin to calcium oxalate crystallization was 14.2%, that of 2gamma-MGlu prothrombin was 12.8%, decreased by about 10%, and that of 8gamma-MGlu prothrombin was 5.0%, decreased by about 65%. CONCLUSIONS The Gla in the Gla domain of urinary prothrombin may play an important role in inhibiting the formation of renal calcium oxalate calculus.
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Affiliation(s)
- Jihong Liu
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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11
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Schmidt AE, Padmanabhan K, Underwood MC, Bode W, Mather T, Bajaj SP. Thermodynamic linkage between the S1 site, the Na+ site, and the Ca2+ site in the protease domain of human activated protein C (APC). Sodium ion in the APC crystal structure is coordinated to four carbonyl groups from two separate loops. J Biol Chem 2002; 277:28987-95. [PMID: 12029084 DOI: 10.1074/jbc.m201892200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serine protease domain of activated protein C (APC) contains a Na+ and a Ca2+ site. However, the number and identity of the APC residues that coordinate to Na+ is not precisely known. Further, the functional link between the Na+ and the Ca2+ site is insufficiently defined, and their linkage to the substrate S1 site has not been studied. Here, we systematically investigate the functional significance of these two cation sites and their thermodynamic links to the S1 site. Kinetic data reveal that Na+ binds to the substrate-occupied APC with K(d) values of approximately 24 mm in the absence and approximately 6 mm in the presence of Ca2+. Sodium-occupied APC has approximately 100-fold increased catalytic efficiency ( approximately 4-fold decrease in K(m) and approximately 25-fold increase in k(cat)) in hydrolyzing S-2288 (H-d-Ile-Pro-Arg-p-nitroanilide) and Ca2+ further increases this k(cat) slightly ( approximately 1.2-fold). Ca2+ binds to the protease domain of APC with K(d) values of approximately 438 microm in the absence and approximately 105 microm in the presence of Na+. Ca2+ binding to the protease domain of APC does not affect K(m) but increases the k(cat) approximately 10-fold, and Na+ further increases this k(cat) approximately 3-fold and decreases the K(m) value approximately 3.7-fold. In agreement with the K(m) data, sodium-occupied APC has approximately 4-fold increased affinity in binding to p-aminobenzamidine (S1 probe). Crystallographically, the Ca2+ site in APC is similar to that in trypsin, and the Na+ site is similar to that in factor Xa but not thrombin. Collectively, the Na+ site is thermodynamically linked to the S1 site as well as to the protease domain Ca2+ site, whereas the Ca2+ site is only linked to the Na+ site. The significance of these findings is that under physiologic conditions, most of the APC will exist in Na2+-APC-Ca2+ form, which has 110-fold increased proteolytic activity.
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Affiliation(s)
- Amy E Schmidt
- Department of Pharmacological & Physiological Sciences, Saint Louis University Health Sciences Center, St. Louis, Missouri 63110, USA
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Naraki T, Kohno N, Saito H, Fujimoto Y, Ohhira M, Morita T, Kohgo Y. gamma-Carboxyglutamic acid content of hepatocellular carcinoma-associated des-gamma-carboxy prothrombin. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1586:287-98. [PMID: 11997080 DOI: 10.1016/s0925-4439(01)00107-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Serum des-gamma-carboxy prothrombin (DCP) is a useful marker for the diagnosis of hepatocellular carcinoma (HCC), but the exact mechanism of its synthesis and its structural properties in liver diseases are unknown. DCP is measured by the monoclonal antibody MU-3. The purpose of this study was to examine the epitope of MU-3 and to characterize the differences in DCP between HCC and benign liver diseases. The epitope of MU-3 was examined by ELISA using prothrombin Gla domain polypeptides and was determined to be amino acid residues 17-27 of the prothrombin Gla domain, which has four gamma-carboxyglutamic acid residues (Gla) at positions 19, 20, 25 and 26. Peptides having a glutamic acid residue (Glu) at these positions reacted strongly to MU-3 but lost reactivity when Glu 19 or 20 was changed to Gla. In the order of gamma-carboxylation, MU-3 reacted strongly to DCP containing 0-1 Gla, weakly to 2-4 Gla and not at all to DCP containing more than five Gla. After adsorbing normal prothrombin with barium carbonate, DCP reaction to MU-3 was measured by determining the amount of DCP that was adsorbed by MU-3-coated beads. The proportion of DCP reacting to MU-3 in HCC was 41.0-76.8%, whereas in patients with benign liver diseases, only 0-42.1% reacted to MU-3. These results indicate that DCP variants preferentially synthesized in HCC have less than four Gla, which are restricted to positions 16, 25, 26 and 29, whereas DCP variants in benign liver diseases have more than five Gla.
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Affiliation(s)
- Toru Naraki
- Tsukuba Research Laboratories, Eisai Co., Ltd., 1-3 Tokodai 5-chome, Ibaraki 300-2635, Japan.
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Brown MA, Stenberg LM, Persson U, Stenflo J. Identification and purification of vitamin K-dependent proteins and peptides with monoclonal antibodies specific for gamma -carboxyglutamyl (Gla) residues. J Biol Chem 2000; 275:19795-802. [PMID: 10779512 DOI: 10.1074/jbc.m002298200] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Novel monoclonal antibodies that specifically recognize gamma-carboxyglutamyl (Gla) residues in proteins and peptides have been produced. As demonstrated by Western blot and time-resolved immunofluorescence assays the antibodies are pan-specific for most or all of the Gla-containing proteins tested (factors VII, IX, and X, prothrombin, protein C, protein S, growth arrest-specific protein 6, bone Gla protein, conantokin G from a cone snail, and factor Xa-like proteins from snake venom). Only the Gla-containing light chain of the two-chain proteins was bound. Decarboxylation destroyed the epitope(s) on prothrombin fragment 1, and Ca(2+) strongly inhibited binding to prothrombin. In Western blot, immunofluorescence, and surface plasmon resonance assays the antibodies bound peptides conjugated to bovine serum albumin that contained either a single Gla or a tandem pair of Gla residues. Binding was maintained when the sequence surrounding the Gla residue(s) was altered. Replacement of Gla with glutamic acid resulted in a complete loss of the epitope. The utility of the antibodies was demonstrated in immunochemical methods for detecting Gla-containing proteins and in the immunopurification of a factor Xa-like protein from tiger snake venom. The amino acid sequences of the Gla domain and portions of the heavy chain of the snake protein were determined.
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Affiliation(s)
- M A Brown
- Department of Clinical Chemistry, Lund University, University Hospital, Malmö, S-205 02 Malmö, Sweden
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Sabharwal AK, Padmanabhan K, Tulinsky A, Mathur A, Gorka J, Bajaj SP. Interaction of calcium with native and decarboxylated human factor X. Effect of proteolysis in the autolysis loop on catalytic efficiency and factor Va binding. J Biol Chem 1997; 272:22037-45. [PMID: 9268343 DOI: 10.1074/jbc.272.35.22037] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Human factor X is a two-chain, 58-kDa, vitamin K-dependent blood coagulation zymogen. The light chain of factor X consists of an NH2-terminal gamma-carboxyglutamic acid (Gla) domain, followed by a few helical hydrophobic residues and the two epidermal growth factor-like domains, whereas the heavy chain contains the serine protease domain. In this study, native factor X was found to contain three classes of Ca2+-binding sites: two high affinity (Kd 100 +/- 30 microM), four intermediate affinity (Kd 450 +/- 70 microM), and five to six low affinity (Kd 2 +/- 0.2 mM). Decarboxylated factor X in which the Gla residues were converted to Glu retained the two high affinity sites (Kd 140 +/- 20 microM). In contrast, factor X lacking the Gla domain as well as a part of the helical hydrophobic residues (des-44-X) retained only one high affinity Ca2+-binding site (Kd 130 +/- 20 microM). Moreover, a synthetic peptide composed of residues 238-277 (58-97 in chymotrypsinogen numbering) from the protease domain of factor X bound one Ca2+ with high affinity (Kd 150 +/- 20 microM). From competitive inhibition assays for binding of active site-blocked factor Xa to factor Va in the prothrombinase complex, the Kd for peptide-Va interaction was calculated to be approximately 10 microM as compared with 30 pM for factor Xa and approximately 1.5 microM for decarboxylated factor Xa. A peptide containing residues 238-262(58-82) bound Ca2+ with reduced affinity (Kd approximately 600 microM) and did not inhibit Xa:Va interaction. In contrast, a peptide containing residues 253-277(73-97) inhibited Xa:Va interaction (Kd approximately 10 microM) but did not bind Ca2+. In additional studies, Ca2+ increased the amidolytic activity of native and des-44-Xa toward a tetrapeptide substrate (benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide) by approximately 1.6-fold. The half-maximal increase was observed at approximately 150 microM Ca2+ and the effect was primarily on the kcat. Ca2+ also significantly protected cleavage at Arg-332-Gln-333(150-151) in the protease domain autolysis loop. Des-44-Xa in which the autolysis loop was cleaved possessed </=5% of the amidolytic activity of the noncleaved form; however, the S1 binding site was not affected, as determined by the p-aminobenzamidine binding. Additionally, autolysis loop-cleaved, active site-blocked native factor Xa was calculated to have approximately 10-fold reduced affinity for factor Va as compared with that of the noncleaved form.
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Affiliation(s)
- A K Sabharwal
- Department of Medicine, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
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Grosley BM, Hirschauer C, Chambrette B, Bezeaud A, Amiral J. Specific measurement of hypocarboxylated prothrombin in plasma or serum and application to the diagnosis of hepatocellular carcinoma. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1996; 127:553-64. [PMID: 8648260 DOI: 10.1016/s0022-2143(96)90146-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An enzyme-linked immunosorbent assay (ELISA) was developed for measuring human hypocarboxyprothrombin, a protein induced by vitamin K antagonists (PIV KA-II). A specific monoclonal antibody (P1-2-B9) was prepared and used for coating a microELISA plate, and revelation proceeded with a rabbit polyclonal anti-human prothrombin antibody-peroxidase conjugate. This assay allowed the measurement of PIVKA-II at concentrations ranging from 2 to 200 ng/ml, with an intraassay coefficient of variation of less than 5.2% and an interassay coefficient of variation of less than 7.4%. This assay permits the direct evaluation of PIVKA-II in citrated plasma as well as in serum. The concentration of PIVKA-II is expressed in nanograms per milliliter. It offers specific measurement of PIVKA-II without any cross-reactivity from native prothrombin: the specificity for PIVKA-II respective to prothrombin is > 10(5). No reactivity was observed with other vitamin K-dependent proteins, whether fully active or decarboxylated. Complementary studies have demonstrated that the monoclonal antibody used was preferentially directed to 3 to 6 Gla hypocarboxylated prothrombin. PIVKA-II concentration was below 2.4 ng/ml in normal individuals (n = 59). In 61 patients given dicoumarol for more than 90 days (receiving a stable therapy), the measured concentrations of PIVKA-II ranged from 750 to 13,400 ng/ml. Combined with the assay of alpha-fetoprotein (AFP), measurement of PIVKA-II in patients with liver diseases introduces a complementary exploration for hepatocellular carcinoma (HCC). In a study in 59 patients with HCC, the assay sensitivity was 49.1% for PIVKA-II, 47.5% for AFP, and 71% for both markers combined.
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Affiliation(s)
- B M Grosley
- SERBIO Research Laboratory, Gennevilliers, France
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Astermark J, Hogg P, Stenflo J. The gamma-carboxyglutamic acid and epidermal growth factor-like modules of factor IXa beta. Effects on the serine protease module and factor X activation. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)41914-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Ratcliffe J, Furie B, Furie B. The importance of specific gamma-carboxyglutamic acid residues in prothrombin. Evaluation by site-specific mutagenesis. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80531-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Astermark J, Hogg P, Björk I, Stenflo J. Effects of gamma-carboxyglutamic acid and epidermal growth factor-like modules of factor IX on factor X activation. Studies using proteolytic fragments of bovine factor IX. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50723-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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19
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Hogg PJ, Ohlin AK, Stenflo J. Identification of structural domains in protein C involved in its interaction with thrombin-thrombomodulin on the surface of endothelial cells. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48340-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Astermark J, Björk I, Ohlin AK, Stenflo J. Structural requirements for Ca2+ binding to the gamma-carboxyglutamic acid and epidermal growth factor-like regions of factor IX. Studies using intact domains isolated from controlled proteolytic digests of bovine factor IX. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52262-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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21
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Persson E, Björk I, Stenflo J. Protein structural requirements for Ca2+ binding to the light chain of factor X. Studies using isolated intact fragments containing the gamma-carboxyglutamic acid region and/or the epidermal growth factor-like domains. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52264-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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22
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Bovill EG, Malhotra OP, Mann KG. Mechanisms of vitamin K antagonism. BAILLIERE'S CLINICAL HAEMATOLOGY 1990; 3:555-81. [PMID: 2271783 DOI: 10.1016/s0950-3536(05)80019-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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23
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Martin BL, Wu D, Tabatabai L, Graves DJ. Formation of cyclic imide-like structures upon the treatment of calmodulin and a calmodulin peptide with heat. Arch Biochem Biophys 1990; 276:94-101. [PMID: 2105083 DOI: 10.1016/0003-9861(90)90014-p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Protein cyclic imide is the putative intermediate in the formation of sites of carboxyl-methylation in eukaryotic proteins. Conditions known to induce the formation of a cyclic imide in model peptides have been applied to a protein, calmodulin. Heating of calmodulin in the dry state at 100 degrees C for 24 h after lyophilization from a pH 2.0 or pH 6.0 solution produces derivatives with altered chromatographic properties in anion-exchange HPLC. At pH 6.0, complete activity of calmodulin was retained. Analysis with Fourier transform infrared (FTIR)-photoacoustic spectroscopy demonstrated the presence of a new structure in the calmodulin molecule consistent with modification of carboxylic acid groups. The conversion of calmodulin is dependent upon the absence of Ca2+ (the presence of 1 mM ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid). A peptide analogous to the calcium binding regions of calmodulin, Asp-Lys-Asp-Gly-Asn-Gly-Thr-Ile-Thr-Thr-Lys-Glu, is also converted, upon heating, to chromatographically different forms in reversed-phase chromatography. This process is also dependent upon the absence of calcium. Sequence analysis of the peptide derivatives reveals a second amino terminus, implicating peptide bond hydrolysis in the product. A dipeptide, Asp-Gly, known to form a cyclic imide structure under similar conditions is also hydrolyzed during sequence analysis consistent with cleavage occurring at the position of the cyclic imide structure. Asp3 is suggested to be the site of cyclic imide formation in the calmodulin peptide. The presence of a cyclic imide structure is also confirmed by the application of FTIR-photoacoustic spectroscopy. These data suggest that cyclic imide formation in calmodulin has been induced, possibly at one, or more, of the calcium binding loops of the protein. These modification reactions may provide a basis for future investigations of cyclic imide formation in proteins.
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Affiliation(s)
- B L Martin
- Department of Biochemistry and Biophysics, Iowa State University, Ames 50011
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24
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Orthner CL, Madurawe RD, Velander WH, Drohan WN, Battey FD, Strickland DK. Conformational changes in an epitope localized to the NH2-terminal region of protein C. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)51535-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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25
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Lecompte MF, Dode C. Interaction of human gamma-carboxyglutamic acid domainless prothrombin with phospholipids. Biochimie 1989; 71:175-81. [PMID: 2497793 DOI: 10.1016/0300-9084(89)90148-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The conversion of prothrombin into thrombin occurs at the surface of stimulated platelets. In order to see the influence of gamma-carboxyglutamic acid in the interaction of prothrombin with phospholipid, we investigated the direct interaction of the peptide 1-41 and prothrombin (des 1-44) with phospholipid monolayers of various compositions. Adsorption of the labeled proteins was determined by surface radioactivity measurements. Penetration of the proteins into the lipid layers was inferred from capacitance variation of the monolayer, measured by a.c. polarography. Prothrombin (des 1-44) was found both to adsorb and to penetrate the lipid monolayers, in the presence and in the absence of Ca++. The effects are higher on 100% PS than on 25% PS. This protein was also found to increase the permeability of vesicles containing 25% PS to T1+ ions, in the presence and in the absence of Ca++. Comparison with prothrombin shows that Gla residues are clearly involved in the interaction at 25% PS; nevertheless, the peptide 1-41 does not penetrate. A model of interaction of prothrombin with phospholipid, including both adsorption of prothrombin by Gla residues and its penetration by another domain, is proposed.
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Affiliation(s)
- M F Lecompte
- Laboratoire d'Electrochimie Interfaciale du CNRS, Meudon, France
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26
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Yanagawa Y, Abe T, Satake M, Odani S, Suzuki J, Ishikawa K. A novel sodium channel inhibitor from Conus geographus: purification, structure, and pharmacological properties. Biochemistry 1988; 27:6256-62. [PMID: 2851318 DOI: 10.1021/bi00417a009] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A novel toxin, tentatively named conotoxin GS (CGS), has been isolated from a marine snail, Conus geographus. CGS was found to exist as a single polypeptide chain, consisting of 34 amino acid residues, cross-linked by three disulfide bonds. Its amino acid sequence was shown to be Ala-Cys-Ser-Gly-Arg-Gly-Ser-Arg-Cys-Hyp-Hyp-Gln-Cys-Cys-Met-Gly-Leu-Arg- Cys-Gly - Arg-Gly-Asn-Pro-Gln-Lys-Cys-Ile-Gly-Ala-His-Gla-Asp-Val. In competition experiments, CGS inhibited the bindings of [3H]Lys-tetrodotoxin ([3H]Lys-TTX) and [3H]propionylconotoxin GIIIA to Electrophorus electricus electroplax membranes, with Ki values of 34 nM and 24 nM, respectively. The toxin inhibited the binding of [3H]Lys-TTX (1 nM) to rat skeletal muscle homogenates with an IC50 value of 880 nM but showed very little effect on this binding to the rat brain P2 fraction at 10 microM. These binding studies indicate that CGS belongs to the same group of Na channel inhibitors as TTX, STX (saxitoxin), and mu-conotoxins. Although CGS, like the mu-conotoxins, is a pharmacological probe for distinguishing between neuronal and muscle Na channel subtypes, the homology in the sequences of CGS and mu-conotoxins is very limited.
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Affiliation(s)
- Y Yanagawa
- Department of Neurochemistry, Brain Research Institute, Niigata University, Japan
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27
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Metal ion blockage of tritium incorporation into gamma-carboxyglutamic acid of prothrombin. Stoichiometry of gamma-carboxyglutamic acid to Gd3+ for the high affinity sites. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)81578-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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28
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A conserved epitope on several human vitamin K-dependent proteins. Location of the antigenic site and influence of metal ions on antibody binding. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68780-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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29
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Lewis MR, Deerfield DW, Hoke RA, Koehler KA, Pedersen LG, Hiskey RG. Studies on Ca(II) binding to gamma-carboxyglutamic acid. Use of thermal decarboxylation to probe metal ion/gamma-carboxyglutamic acid interactions. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)57310-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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30
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Jüppner H, Schettler T, Giebel G, Wenner S, Hesch RD. Radioimmunoassay for human osteocalcin using an antibody raised against the synthetic human (h37-49) sequence. Calcif Tissue Int 1986; 39:310-5. [PMID: 3102020 DOI: 10.1007/bf02555196] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Radioiodination of synthetic human 37-49 osteocalcin requires optimal labeling conditions in order to obtain a maximum of mono- and di-iodinated tracer with little contamination by tri- and tetra-iodinated products or "radio-damage." The antibody raised against osteocalcin(h37-49) had the highest affinity for the C-terminal peptide used for iodination and the larger peptide (h30-49). The intact bovine osteocalcin (b1-49) revealed less immunoreactivity. This C-terminal specific radioimmunoassay detected the intact human osteocalcin in HPLC purified plasma and peritoneal dialysate from patients with terminal renal insufficiency and in extracted human bone. Some quantities of osteocalcin peptides with a higher hydrophobicity were predominantly detected in uremic plasma. These peptides that had a higher molecular weight than the intact human molecule might represent aggregated forms of the intact bone-derived osteocalcin. Immunoreactivity in plasma samples from healthy individuals revealed a remarkable difference as to which substance was employed for anticoagulation. Compared to heparin, the addition of EDTA largely reduced the osteocalcin immunoreactivity, implying that conformational changes within the N-terminal portion (containing the Gla- and Cys-residues) are extended to the C-terminal portion.
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31
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Walker FJ. Properties of chemically modified protein S: effect of the conversion of gamma-carboxyglutamic acid to gamma-methyleneglutamic acid on functional properties. Biochemistry 1986; 25:6305-11. [PMID: 2947625 DOI: 10.1021/bi00368a071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Protein S, the protein cofactor for activated protein C in the proteolytic inactivation of factor Va, was chemically modified with a mixture of morpholine and formaldehyde. This treatment resulted in the conversion of the gamma-carboxyglutamic acid (Gla) residues of this vitamin K dependent protein to gamma-methyleneglutamic acid. With a 10,000-fold molar excess of morpholine and formaldehyde over protein S it was found that between 10 and 11 Gla residues could be modified. The degree of modification was proportional to the concentration of the modifying reagents used. The modification of as few as two residues resulted in the 70% loss of activity. Calcium inhibited the modification of several residues. In the presence of 3.2 mM calcium ion, a derivative with 2.5 residues modified was prepared that appeared to have full activity. Modification of protein S resulted in the alteration of a number of its properties. The quenching of intrinsic fluorescence by calcium decreased. The quenching effect of terbium ions was also decreased. However, the modified protein and the native protein were equivalent when protein-dependent terbium fluorescence was measured. When modified, protein S would no longer bind to phospholipid vesicles. Finally, the ability of protein S to self-associate was decreased by modification. These findings suggest that the gamma-carboxyglutamic acid residues of protein S may play several roles in the maintenance of structure.
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32
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Wright SF, Berkowitz P, Deerfield DW, Byrd PA, Olson DL, Larson RS, Hinn GC, Koehler KA, Pedersen LG, Hiskey RG. Chemical modification of bovine prothrombin fragment 1 in the presence of Tb3+ ions. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67427-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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33
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The effect of divalent metal ions on the electrophoretic mobility of bovine prothrombin and bovine prothrombin fragment 1. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)89180-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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34
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Tarvers RC, Noyes CM, Tarvers JK, Lundblad RL. Mechanism of the calcium-dependent self-association of bovine prothrombin. Use of a covalent cross-linking reagent to study the reaction. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)89183-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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35
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Borowski M, Furie BC, Goldsmith GH, Furie B. Metal and phospholipid binding properties of partially carboxylated human prothrombin variants. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)39361-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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36
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Straight DL, Sherrill GB, Noyes CM, Trapp HG, Wright SF, Roberts HR, Hiskey RG, Griffith MJ. Structural and functional characteristics of activated human factor IX after chemical modification of gamma-carboxyglutamic acid residues. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(18)89448-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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37
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Zell A, Einspahr H, Bugg CE. Model for calcium binding to gamma-carboxyglutamic acid residues of proteins: crystal structure of calcium alpha-ethylmalonate. Biochemistry 1985; 24:533-7. [PMID: 3978091 DOI: 10.1021/bi00323a043] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The crystal structure of a Ca2+ salt of alpha-ethylmalonic acid was determined from three-dimensional X-ray diffraction data. The dicarboxylate anion represents the functional side chain of gamma-carboxyglutamic acid (Gla) residues, which are implicated as essential calcium-binding ligands in a variety of proteins. The alpha-ethylmalonate ion chelates the Ca2+ ion in a bidentate manner that involves an O atom from each of the two malonate carboxylate groups. This type of binding arises from the constrained arrangement of carboxylate ligands in the malonate group and may be of significance to the calcium-binding properties of Gla-containing sites in proteins. The Ca2+-malonate chelation forms a six-membered ring, which is stabilized by interactions that are consistent with the preferred stereochemistries of both calcium-carboxylate and metal-malonate complexes. No other interactions are observed between Ca2+ ions and alpha-ethylmalonate ions that depend upon the malonate juxtaposition of two carboxylate groups. The potential for this type of binding distinguishes Gla residues from the monocarboxylate residues, aspartate and glutamate, and confers a novel calcium-chelation ability upon Gla-containing sites in proteins.
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38
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Sherrill GB, Straight DL, Hiskey RG, Roberts HR, Griffith MJ. Inactivation of human blood coagulation factor X by chemical modification of gamma-carboxyglutamic acid residues. Biochem Biophys Res Commun 1984; 124:256-61. [PMID: 6497880 DOI: 10.1016/0006-291x(84)90945-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The inactivation of human factor X by incubation with a reagent known to chemically modify gamma-carboxyglutamic acid to gamma-methylene glutamic acid was studied. Incubation of factor X at pH 5.0 with a preincubated formaldehyde/morpholine mixture (0.9 M/1.0 M) resulted in a progressive decrease in factor X coagulant activity. In the presence of calcium (20 mM) the rate of factor X inactivation was decreased -3-fold. By using [14]C-formaldehyde, modified-factor X (less than 5% residual activity) was found to contain 7 mols of [14]C per mol of protein. Modified-factor X was not activated by Russell's viper venom in the presence of calcium, suggesting that the loss of coagulant activity was related to the inability of modified-factor X to be activated.
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39
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Wright SF, Bourne CD, Hoke RA, Koehler KA, Hiskey RG. A method for specific chemical modification of γ-carboxyglutamic acid residues in proteins. Anal Biochem 1984; 139:82-90. [PMID: 6547575 DOI: 10.1016/0003-2697(84)90392-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A method for the chemical modification of gamma-carboxyglutamic acid (Gla) residues in proteins is introduced that has the combined advantages of mildness, a high degree of specificity, and the ability to introduce a radiolabel at modification sites for ease in quantitation. Unlike other Gla modification procedures which are performed in the lyophilized state at 110 degrees C, this procedure is carried out in solution at 37 degrees C. The addition of morpholine and formaldehyde to a slightly acidic solution of bovine prothrombin fragment 1 (residues 1-156) results in the conversion of Gla residues to gamma- methyleneglutamic acid (gamma- MGlu ). The extent of modification is controlled by the relative amounts of modification reagents to protein. A 100-fold molar excess of reagents to fragment 1 produced a protein molecule containing two gamma- MGlu residues, while a modification run at 10,000-fold molar excess of reagents to protein yielded fragment 1 containing eight gamma- MGlu residues per molecule. The specificity of this modification is illustrated by the interaction of native and modified protein with antibody populations directed against fragment 1. Native fragment 1, 8 gamma- MGlu fragment 1, and 2 gamma- MGlu fragment 1 show fairly similar behavior toward whole anti-fragment 1 serum. Differential behavior was exhibited by the native and modified proteins toward a subpopulation of antibodies specific to the calcium ion conformation of fragment 1. Unmodified fragment 1 displayed a strong affinity for these antibodies; however, the 2 gamma- MGlu fragment 1 exhibited a moderate affinity and the 8 gamma- MGlu fragment 1 did not bind to these antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)
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40
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41
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Price PA, Nelson C, Williamson MK. Chemical modification of gamma-carboxyglutamic acid, the vitamin K-dependent amino acid which binds Ca2+. Anal Biochem 1984; 136:119-26. [PMID: 6711802 DOI: 10.1016/0003-2697(84)90313-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
gamma-Carboxyglutamic acid (Gla), the vitamin K-dependent Ca2+ binding amino acid, can be chemically modified in several specific reactions. Practical outlines of the published procedures for the thermal decarboxylation of Gla to Glu in dry proteins and the specific exchange labeling of the gamma-proton of Gla with tritium are presented. The applications of these procedures in the analysis of the role of Gla residues in Ca2+ binding and in biological activity are also discussed. In addition, the reversible formation of pyro-gamma-carboxyglutamic acid is described for the first time. Pyro-gamma-carboxyglutamic acid is formed from Gla in over 99% yield in a first-order reaction with a half-time of 3.5 h at pH 10 and 110 degrees C. The mass spectrum of the dimethyl ester of the reaction adduct is consistent with pyro-gamma-carboxyglutamic acid and treatment of the reaction adduct with 2 M KOH for 24 h at 110 degrees C quantitatively regenerates Gla. The applications of this reversible reaction to the quantitative analysis of Gla in proteins are discussed.
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42
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Ellis V, Scully M, Kakkar V. The effect of divalent metal cations on the inhibition of human coagulation factor Xa by plasma proteinase inhibitors. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 747:123-9. [PMID: 6192845 DOI: 10.1016/0167-4838(83)90130-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The inactivation of human coagulation factor Xa by the plasma proteinase inhibitors alpha 1-antitrypsin, antithrombin III and alpha 2-macroglobulin in purified systems was found to be accelerated by the divalent cations Ca2+, Mn2+ and Mg2+. The rate constant for the inhibition of factor Xa by antithrombin III rose from 2.62 X 10(4) M-1 X min-1 in the absence of divalent cations to a maximum of 6.40 X 10(4) M-1 X min-1 at 5 mM Ca2+, 8.10 X 10(4) M-1 X min-1 at 5 mM Mn2+, with a slight decrease in rate at higher cation concentrations. Mg2+ caused a gradual rise in rate constant to 5.65 X 10(4) M-1 X min-1 at 20 mM. The rate constant for the inhibition of factor Xa by alpha 1-antitrypsin in the absence of divalent cations was 5.80 X 10(3) M-1 X min-1. Ca2+ increased the rate to 1.50 X 10(4) M-1 X min-1 at 5 mM and Mn2+ to 2.40 X 10(4) M-1 X min-1 at 6 mM. The rate constant for these cations again decreased at higher concentrations. Mg2+ caused a gradual rise in rate constant to 1.08 X 10(4) M-1 X min-1 at 10 mM. The rate constant for the factor Xa-alpha 2-macroglobulin reaction was raised from 6.70 X 10(3) M-1 X min-1 in the absence of divalent cations to a maximum of 4.15 X 10(4) M-1 X min-1 at 4 mM Ca2+, with a decrease to 3.05 X 10(4) M-1 at 10 mM. These increases in reaction rate were correlated to the binding of divalent cations to factor Xa by studying changes in the intrinsic fluorescence and dimerization of factor Xa. The changes in fluorescence suggested a conformational change in factor Xa which may be responsible for the increased rate of reaction, whilst the decrease in rate constant at higher concentrations of Ca2+ and Mn2+ may be due to factor Xa dimerization.
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43
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Gundlach G, Voegeli R. Conformational changes of 4-carboxyglutamic acid-containing protein from bovine bone by binding of alkaline earth ions. HOPPE-SEYLER'S ZEITSCHRIFT FUR PHYSIOLOGISCHE CHEMIE 1983; 364:31-9. [PMID: 6601608 DOI: 10.1515/bchm2.1983.364.1.31] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The effect of magnesium, calcium, and strontium ions on the bovine bone Gla protein were studied by CD spectroscopy, UV difference spectroscopy and the binding of magnesium and calcium ions was studied by equilibrium dialysis. CD measurements indicate an increase of alpha-helix upon addition of alkaline earth ions. UV difference spectra show a change in the environment of a tyrosine residue. Evaluation of the results of all three studies indicate positive cooperativity in binding of calcium and strontium ions and negative or no cooperativity in binding of magnesium ions.
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44
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Bajaj SP. Cooperative Ca2+ binding to human factor IX. Effects of Ca2+ on the kinetic parameters of the activation of factor IX by factor XIa. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34695-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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