Chemical and immmunochemical characterization of the functional domains of hemopexin

Journal Article · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5022174

Muster, P; Tatum, F M; McConnell, J; Smith, A; Morgan, W T; Conway, T P

Plasmin cleaves rabbit serum hemopexin (HPX; Mr 60000) into domain I which binds heme (Mr 35000) and domain II (Mr 25000) which may act in receptor binding. Modification with diethyl-pyrocarbonate of the 5 histidine (his) residues of domain I abolishes the normal spectrum of bound heme. Only 3 his of the heme-domain I complex were modified. These data indicate bis-histidyl coordination of heme in the domain as in intact HPX. Monoclonal antibodies were obtained by fusing mouse FOX NY myeloma cells with spleen cells from DBA mice immunized with rabbit heme-HPX. Of four stable hybridoma lines producing IgG/sub 1/, kappa type, JEN-1, -3 and-14 recognize the heme-binding domain I and JEN-11 recognizes domain II. Antibodies were bound to 12.5 nM mesoheme-/sup 125/I-HPX by incubating with 25 or 250 nM IgG before carrying out receptor binding studies with mouse Hepa cells. Only JEN-14 inhibited specific binding of heme-HPX to its receptor. JEN-11 had no effect on binding. Competitive inhibition experiments revealed that domains I and II interact with the receptor when presented to the cells as an equimolar complex with heme but not alone.

• Research Organization: Louisiana State Univ. Medical Center, New Orleans
• OSTI ID: 5022174
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:6; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HEME
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYBRIDOMAS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MICE
MONOCLONAL ANTIBODIES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PIGMENTS
PORPHYRINS
PROTEINS
RABBITS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RODENTS
SOMATIC CELLS
SPLEEN CELLS
TRACER TECHNIQUES
TUMOR CELLS
VERTEBRATES