title: Structural and functional analysis of spectrin from neonatal erythrocytes.
abstract: Spectrin was purified by rate zonal sedimentation from low-salt extracts of red cell membranes from neonatal and adult blood. Neonatal and adult spectrin cosedimented in sucrose density gradients, comigrated on SDS gels and displayed identical two-dimensional chymotryptic 125I-labelled peptide maps. Neonatal spectrin and adult spectrin exhibited equivalent affinity for both neonatal and adult ankyrin sites on spectrin-depleted inverted membrane vesicles. Purified spectrin heterodimers from neonatal and adult red cells displayed similar self-association equilibrium constants in a fluid phase dimer-dimer association assay. These results suggest that the unique membrane characteristics of the neonatal erythrocyte are not due to a structural or functional alteration of spectrin. Several alternative hypotheses involving other membrane proteins and their linkages are discussed.
mesh_terms: D002499:Centrifugation, Density Gradient; D002918:Chymotrypsin / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000032:analysis*; D005260:Female; D005312:Fetal Blood / Q000032:analysis*; D006801:Humans; D011247:Pregnancy; D013049:Spectrin / Q000032:analysis*; D013329:Structure-Activity Relationship
chemical_list: D013049:Spectrin; D002918:Chymotrypsin