Isolation of an iron-binding protein from the hemolymph of the horseshoe crab (Limulus polyhemus)
The presence of an iron-binding protein in the hemolymph of Limulus was detected by gel-filtration of /sup 59/Fe-labeled hemolymph. This protein was easily separated from hemocyanin, the oxygen transport protein that constitutes greater than 90% of the protein of Limulus hemolymph. The amount of the Limulus iron-binding protein (LIBP) in hemolymph samples prepared under sterile and non-sterile conditions was identical. LIBP was purified to homogeneity by ion-exchange chromatography. The molecular weight of purified LIBP was estimated by gel-filtration to be 282,000 + 10,000. SDS-electrophoresis demonstrated that LIBP was an oligomeric protein composed of subunits with a molecular weight of 28,000 +/- 2000. The isoelectric point of LIBP was 6.5 as determined by electrofocusing. No /sup 49/Fe was removed from purified LIBP by extensive dialysis with EDTA or 2,2'-dipyridyl. Purified, unlabeled LIBP efficiently sequestered /sup 59/Fe in the absence of hemolymph indicating that no other hemolymph factors are required for the incorporation of iron into LIBP. The isolation of LIBP would support the proposal that the development of specific iron-binding and transport proteins was not necessarily coupled to the development of hemoglobin as a means to accomplish oxygen transport.
- Research Organization:
- Univ. of Richmond, VA
- OSTI ID:
- 6374793
- Report Number(s):
- CONF-870644-; TRN: 87-033968
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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PROTEINS
BIOCHEMICAL REACTION KINETICS
FRACTIONATION
CRABS
ELECTROPHORESIS
ION EXCHANGE CHROMATOGRAPHY
IRON
IRON 59
MOLECULAR WEIGHT
TRACER TECHNIQUES
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHROMATOGRAPHY
CRUSTACEANS
DAYS LIVING RADIOISOTOPES
DECAPODS
ELEMENTS
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
INVERTEBRATES
IRON ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
METALS
NUCLEI
ORGANIC COMPOUNDS
RADIOISOTOPES
REACTION KINETICS
SEPARATION PROCESSES
TRANSITION ELEMENTS
550201* - Biochemistry- Tracer Techniques