Antiheparin proteins secreted by human platelets. Purification, characterization, and radioimmunoassay. [/sup 125/I tracer techniques]
- Temple Univ. Health Sciences Center, Philadelphia, PA
Platelet factor 4 (PF4) and low-affinity PF4 (LA-PF4) were purified to homogeneity from washed human platelets by ZnSO/sub 4/ precipitation and affinity chromatography on heparinagarose columns. As shown by double immunodiffusion and specific radioimmunoassays, LA-PF4 and PF4 were immunologically distinct. The levels of PF4 and LA-PF4 antigens in intact platelets were 12.4 and 24.2 ..mu..g/10/sup 9/ platelets, respectively. Heparin-neutralizing activity was assayed by measuring the degree of hydrolysis of the chromogenic substrate Bz-IIe-Glu-Gly-Arg-pNA in the presence of antithrombin III and heparin; 1 mg each of PF4 and LA-PF4 neutralized 17.0 and 2.6 units of beef lung heparin, respectively. Both proteins accounted for 28% of the total heparin neutralizing activity of the platelets. The molecular weight of LA-PF4 as calculated by amino acid analysis and SDS polycrylamide gel electrophoresis was 9070 and 7800 daltons, respectively. LA-PF4 shared common antigenic determinants with ..beta..-thromboglobulin (..beta..TG) and connective tissue-activating peptide III. The difference between LA-PF4 and ..beta..TG was shown by electrophoresis on cellulose acetate at pH 8.6. LA-PF4 migrated in the ..gamma.. globulin region, in contrast to ..beta..TG, which migrated in the ..beta.. globulin region. The NH/sub 2/ terminal amino acids of LA-PF4 and ..beta..TG were asparagine and glycine, respectively. Partial amino acid sequencing of LA-PF4 showed differences between this protein and ..beta..TG. At the NH/sub 2/-terminal end LA-PF4 had four additional amino acids (Asn-Leu-Ala-Lys); however, residues 5-12 of LA-PF4 and 1-8 of ..beta..TG were identical.
- OSTI ID:
- 6471451
- Journal Information:
- Blood; (United States), Journal Name: Blood; (United States) Vol. 53:1; ISSN BLOOA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINES
AMINO ACIDS
ANTIBODIES
ANTICOAGULANTS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CARBOHYDRATES
CARBOXYLIC ACIDS
DATA
DATA FORMS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
EXPERIMENTAL DATA
GRAPHS
HEPARIN
INFORMATION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MUCOPOLYSACCHARIDES
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
POLYSACCHARIDES
PROTEINS
PURIFICATION
RADIOASSAY
RADIOIMMUNOASSAY
RADIOISOTOPES
SACCHARIDES
TRACER TECHNIQUES