Activated Human Hageman Factor (XII)*

Speer, R. J.; Ridgway, Helen; Hill, Joseph M.

doi:10.1055/s-0038-1654849

Cited by 19 publications

(10 citation statements)

References 18 publications

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“…The average SD was found to be 0.71%. Also listed for comparison are the values previously published for the amino acid analysis of human HF by Speer, Ridgway, and Hill (47). We agree on the large number of charged residues present, but discrepancies in the amounts of several residues, most notably cysteine, were observed.…”

Section: Resultssupporting

confidence: 81%

The Secondary Structure of Human Hageman Factor (Factor XII) and its Alteration by Activating Agents

McMillin¹,

Saito²,

Ratnoff³

et al. 1974

J. Clin. Invest.

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A B S T R A C T Hageman factor (factor XII) is activated by exposure to surfaces such as glass or by solutions of certain compounds, notably ellagic acid. Changes in the structure of Hageman factor accompanying activation have been examined in this study by circular dichroism spectroscopy. The spectrum of unactivated Hageman factor in aqueous solutions suggests that its conformation is mainly aperiodic. Various perturbants altered the conformation of Hageman factor in differing ways, demonstrating the sensitivity of Hageman factor to its environment.After activation of Hageman factor with solutions of ellagic acid, a negative trough appeared in the region of the circular dichroism spectrum commonly assigned to tyrosine residues, along with other minor changes in the peptide spectral region. Some of these changes are similar to changes that occurred upon partial neutralization of the basic residues at alkali pH. Activation of Hageman factor by adsorption to quartz surfaces (in an aqueous environment) also produced changes similar to those in the ellagic acid-activated Hageman factor, including the negative ellipticity in the tyrosine region.These observations suggest that the activation process may be related to a change in status of some of the basic amino acid residues, coupled with a specific change in the environment of some tyrosine residues. The importance of these changes during the activation process remains to be determined. The

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Section: Resultssupporting

confidence: 81%

The Secondary Structure of Human Hageman Factor (Factor XII) and its Alteration by Activating Agents

McMillin¹,

Saito²,

Ratnoff³

et al. 1974

J. Clin. Invest.

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“…The studies presented in this paper were done with the aim of obtaining functionally pure factor XII a, contact activation product or factor Xla, and kinin-forming substances. Speer et al (45) reported to have obtained activated factor XII from human plasma by adsorption to and desorption from celite, followed by several preparative steps. The purified substance isolated by these investigators although migrating as a y-globulin, at pH 8.6, had an apparent isoelectric point of 5.2, eluted with increasing pH during cation-exchange chromatography and h ad an estimated molecular weight of about 20,000 by sedimentation equilibrium, but above 100,000 by gel filtration.…”

Section: Discussionmentioning

confidence: 99%

“…This was based on the method of Speer et al ( 45) modified as follows: The celite ("Hyflo", Super Ce!, Johns-Manville, Port Credit, Ontario) was suspended in 0.001 M Tris HCl (pH 8.0). The excess buffer was separated by centrifugation and the celite evenly suspended in the plasma (150 mg celite per ml plasma).…”

Section: P Reparation Of Celite Eluatesmentioning

confidence: 99%

The Kinin System of Human Plasma

Özge-Anwar¹,

Movat²,

Scott³

1972

Thromb Haemost

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SummaryHuman plasma was adsorbed to celite. The celite eluates were chromatographed on QAE-Sephadex A-50, followed by gel filtration, isoelectric focusing and preparative polyacrylamide electrophoresis.By anion-exchange chromatography, factor XI a, kallikrein and y-globulin were isolated from the excluded protein peak. Factor XIa (MW ∼170,000) corrected the deficiency in plasmas deficient in factors XII or XI, but had no effect on the kininsystem. Its isoelectric point was about 8.0-8.5. Kallikrein had a molecular weight of ∼ 90,000 and a pi of 7.8-8.0 The two substances could be isolated also by polyacrylamide electrophoresis.Highly anionic fractions contained a fragment of factor XII a (prekallikrein activator), which activated prekallikrein and retained some of the clot-promoting property of the intact factor XIIa molecule. Its molecular weight was about 37,000, the pi about 4.4 and it migrated as a prealbumin by disc electrophoresis.It is concluded that, by massive contact exposure, most of factor XII a converts to the highly anionic, low-molecular-weight prekallikrein activator. Since the prekallikrein activator is a fragment of factor XII a, we recommend that it be referred to as “XII f”.

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“…Received for publication 2 September 1975 and in revised form 9 December 1975. plasma. Until recently, however, information concerning the molecular structure of the protein has been sparse and sometimes conflicting (2)(3)(4)(5)(6).…”

Section: Introductionmentioning

confidence: 99%

“…Until recently, however, information concerning the molecular structure of the protein has been sparse and sometimes conflicting (2)(3)(4)(5)(6). The confusion has been undoubtedly due, in part, to the multiple forms of the enzymatically active Hageman factor moiety that result from differing purification and manipulatory techniques used by various investigators.…”

Section: Introductionmentioning

confidence: 99%