Human Platelet Factor 4 (PF 4) Disappearance in Rabbits Fed an Atherogenic Diet

1986 ◽  
Vol 55 (01) ◽  
pp. 146-146 ◽  
Author(s):  
Marco Prosdocimi ◽  
Alberto Zatta ◽  
Fabrizio Fabris ◽  
Giuseppe Cella
Keyword(s):  
Human Platelet ◽  
Atherogenic Diet ◽  
Platelet Factor 4 ◽  
Platelet Factor

Half-Life of Platelet Factor 4 (PF-4) in Plasma and Platelets from Macaca Mulatta

1977 ◽  
Vol 37 (01) ◽  
pp. 073-080 ◽  
Author(s):  
Knut Gjesdal ◽  
Duncan S. Pepper
Keyword(s):  
Macaca Mulatta ◽  
Half Life ◽  
Human Platelet ◽  
Gel Filtration ◽  
Platelet Factor 4 ◽  
Active Protein ◽  
Platelet Factor ◽  
Membrane Bound

SummaryHuman platelet factor 4 (PF-4) showed a reaction of complete identity with PF-4 from Macaca mulatta when tested against rabbit anti-human-PF-4. Such immunoglobulin was used for quantitative precipitation of in vivo labelled PF-4 in monkey serum. The results suggest that the active protein had an intra-platelet half-life of about 21 hours. In vitro 125I-labelled human PF-4 was injected intravenously into two monkeys and isolated by immuno-precipita-tion from platelet-poor plasma and from platelets disrupted after gel-filtration. Plasma PF-4 was found to have a half-life of 7 to 11 hours. Some of the labelled PF-4 was associated with platelets and this fraction had a rapid initial disappearance rate and a subsequent half-life close to that of plasma PF-4. The results are compatible with the hypothesis that granular PF-4 belongs to a separate compartment, whereas membrane-bound PF-4 and plasma PF-4 may interchange.

Complete Covalent Structure of Human Platelet Factor 4

1979 ◽  
Vol 42 (05) ◽  
pp. 1652-1660 ◽  
Author(s):  
Francis J Morgan ◽  
Geoffrey S Begg ◽  
Colin N Chesterman
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Human Platelet ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
Disulphide Bonds ◽  
Covalent Structure

SummaryThe amino acid sequence of the subunit of human platelet factor 4 has been determined. Human platelet factor 4 consists of identical subunits containing 70 amino acids, each with a molecular weight of 7,756. The molecule contains no methionine, phenylalanine or tryptophan. The proposed amino acid sequence of PF4 is: Glu-Ala-Glu-Glu-Asp-Gly-Asp-Leu-Gln-Cys-Leu-Cys-Val-Lys-Thr-Thr-Ser- Gln-Val-Arg-Pro-Arg-His-Ile-Thr-Ser-Leu-Glu-Val-Ile-Lys-Ala-Gly-Pro-His-Cys-Pro-Thr-Ala-Gin- Leu-Ile-Ala-Thr-Leu-Lys-Asn-Gly-Arg-Lys-Ile-Cys-Leu-Asp-Leu-Gln-Ala-Pro-Leu-Tyr-Lys-Lys- Ile-Ile-Lys-Lys-Leu-Leu-Glu-Ser. From consideration of the homology with p-thromboglobulin, disulphide bonds between residues 10 and 36 and between residues 12 and 52 can be inferred.

Clearance and In Vivo Release by Heparin of Human Platelet Factor 4 (PF4) in the Rabbit

1984 ◽  
Vol 52 (02) ◽  
pp. 157-159 ◽  
Author(s):  
M Prosdocimi ◽  
N Scattolo ◽  
A Zatta ◽  
F Fabris ◽  
F Stevanato ◽  
...  
Keyword(s):  
Half Life ◽  
Human Platelet ◽  
Slow Component ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
In Vivo Release ◽  
Partial Release ◽  
Different Doses ◽  
New Zealand Rabbits

Summary13 male New Zealand rabbits were injected with two different doses (25 μg/Kg and 100 μg/Kg) of human platelet factor 4 antigen (PF4). The disappearance of the protein was extremely fast with an half-life for the fast component of 1.07 ± 0.16 and 1.76 ± 0.11 min respectively. The half-life for the slow component, detectable only with the highest dosage, was 18.8 min.The administration of 2500 I.U. of heparin 30 min after PF4 administration induced a partial release of the injected protein and its clearance from plasma was slow, with half-life of 23.3 ± 5.9 min and 30.9 ± 2.19 min respectively.

Polycistronic Expression of Human Platelet Factor 4 with Heparin-Neutralizing Activity inEscherichia coli

2012 ◽  
Vol 76 (10) ◽  
pp. 1855-1860 ◽  
Author(s):  
Yitao DUAN ◽  
Zhe WANG ◽  
Wei WU ◽  
Zhenjiang FANG ◽  
He HUANG
Keyword(s):  
Human Platelet ◽  
Platelet Factor 4 ◽  
Inescherichia Coli ◽  
Platelet Factor ◽  
Neutralizing Activity

A double antibody sandwich microelisa for measuring human platelet factor 4

1985 ◽  
Vol 37 (5) ◽  
pp. 573-582 ◽  
Author(s):  
H.-J. Bauch ◽  
K. Ilsemann ◽  
H. Beeck ◽  
B. Voss ◽  
L. Balleisen
Keyword(s):  
Human Platelet ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
Double Antibody

scholarly journals The multiple complexes formed by the interaction of platelet factor 4 with heparin

1980 ◽  
Vol 191 (3) ◽  
pp. 769-776 ◽  
Author(s):  
P E Bock ◽  
M Luscombe ◽  
S E Marshall ◽  
D S Pepper ◽  
J J Holbrook
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Chain Length ◽  
Salt Concentration ◽  
Human Platelet ◽  
Platelet Factor 4 ◽  
High Protein ◽  
Platelet Factor ◽  
The Stability ◽  
Very High

The anisotropy of the fluorescence of dansyl (5-dimethylaminonaphthalene-1- sulphonyl) groups covalently attached to human platelet factor 4 was used to detect the macromolecular compounds formed when the factor was mixed with heparin. At low heparin/protein ratios a very-high-molecular-weight compound (1) was formed that dissociated to give a smaller compound (2) when excess heparin was added. 2. A large complex was also detected as a precipitate that formed at high protein concentrations in chloride buffer. It contained 15.7% (w/w) polysaccharide, equivalent to four or five heparin tetrasaccharide units per protein tetramer. In this complex, more than one molecule of protein binds to each heparin molecule of molecular weight greater than about 6 × 10(3).3. The stability of these complexes varied with pH, salt concentration and the chain length of the heparin. The limit complexes found in excess of the larger heparins consisted of only one heparin molecule per protein tetramer, and the failure to observe complexes with four heparin molecules/protein tetramer is discussed.

scholarly journals Purification of two heparin-binding proteins from porcine platelets and their homology with human secreted platelet proteins

Blood ◽  
1983 ◽  
Vol 61 (6) ◽  
pp. 1072-1080 ◽  
Author(s):  
B Rucinski ◽  
A Poggi ◽  
P James ◽  
JC Holt ◽  
S Niewiarowski
Keyword(s):  
Amino Acid ◽  
Basic Protein ◽  
Human Platelet ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Cross Reactivity ◽  
Platelet Factor 4 ◽  
Heparin Binding ◽  
Platelet Factor ◽  
Heterologous Antigens

Abstract Two heparin-neutralizing proteins secreted by thrombin-stimulated platelets were purified to homogeneity by means of heparin-agarose affinity chromatography. These proteins, termed porcine platelet basic protein (PBP) and porcine platelet factor 4 (PF4), were eluted from a heparin-agarose column at 0.6–0.9 M NaCl and at 1–1.4 M NaCl, respectively. The molecular weight of porcine platelet basic protein was 7,000–7,700 daltons, as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and amino acid analysis. The isoelectric point of this protein was at pH 9.0. The amino acid composition of porcine platelet basic protein resembled that of human low affinity platelet factor 4 (LA-PF4), except that the porcine protein did not contain tyrosine. The molecular weight of porcine platelet factor 4 ranged from 10,000 (estimated from amino acid analysis) to 14,000 (estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis). The amino acid compositions of human platelet factor 4 and of porcine platelet factor 4 were similar. Monospecific antibodies against porcine platelet factor 4 and porcine platelet basic protein were raised in rabbits. Competitive radioimmunoassay demonstrated a low but significant immunologic cross-reactivity between human and porcine platelet factor 4, and between porcine platelet basic protein and a group of human secreted platelet proteins that bind to heparin with low affinity (beta-thromboglobulin [beta TG] and low affinity platelet factor 4). Experiments with direct immuno- precipitation of 125I-labeled antigens suggested that all four proteins investigated (human platelet factor 4, porcine platelet factor 4, human low affinity platelet factor 4 or human beta-thromboglobulin, and porcine platelet basic protein) share common antigenic determinants. However, there was a higher degree of immunologic cross-reactivity between heterologous antigens with similar heparin binding affinity (human platelet factor 4 and porcine platelet factor 4) than between heterologous antigens with different binding affinity (human platelet factor 4 and porcine platelet basic protein). In conclusion, our finding suggests a significant structural homology among the four proteins.

scholarly journals Primary Structure of Human Platelet Factor 4.

1977 ◽  
Author(s):  
F.J. Morgan ◽  
G.S. Begg ◽  
C.N. Chesterman
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Structural Information ◽  
Human Platelet ◽  
Specific Protein ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
Tryptic Peptides

The amino acid sequence of human platelet factor 4 (PF4) has been studied. PF4 is a platelet specific protein with antiheparin activity, released from platelets as a proteoglycan complex, whose measurement may provide an important index of platelet activation both in vivo and in vitro. These studies were undertaken to characterize fully the PF4 molecule. PF4 is a stable tetramer, composed of identical subunits, each with a molecular weight based on the sequence studies of approx. 7,770. Each PF4 subunit contains 69 amino acids, including 4 half-cystine (# 10, 12, 36, 37), one tyrosine (# 59), 3 arginine and 8 lysine, but no methionine, phenylalanine or tryptophan residues. The basic residues are predominantly in the C-terminal region. The tryptic peptides were aligned after studies which included tryptic digestion of citraconylated RCM-PF4, and automated Edman degradation of RCM-PF4 and citraconylated tryptic peptides. No glycopeptides were detected. This structural information should enable clear distinction to be made between PF4 and other platelet proteins such as β thromboglobulin. The provisional amino acid sequence of each subunit is:Glu-Ala-Glu-Glu-Asp-Gly-Asp-Leu-Gln-Cys-Leu-Cys-Val-Lys-Thr-Thr-Ser-Gln-Val-Arg-Pro-Arg-His-Ile-Thr-Ser-Leu-Glu-Val-Ile-Lys-Ala-Gly-Pro-His-Cys-Cys-Pro-Thr-Ala-Gln-Ile-Leu-Ala-Thr-Leu-Lys-Asn-Gly-Arg-Lys-Ile-Pro-Leu-Asp-Leu-Gln-Ala-Tyr-Leu-Lys-Ile-Lys(Lys, Lys, Ser, Glx, Leu, Leu)

Sign in / Sign up

Export Citation Format

Share Document