Erythrocruorin of Glossoscolex paulistus (Oligochaeta, Glossoscolecidae): modulation of oxygen affinity by specific antibodies.
1) The Soret region absorption spectrum of erythrocruorin (ERC) obtained from Glossoscolex paulistus, shows that oxy-ERC has a maximum absorption peak at 416 nm while the deoxy-ERC from has a maximum at 427 nm. 2) In the presence of a specific antiserum (anti-ERC) and of anti-ERC immunoglobulin G raised in rabbits, there is a deviation to low wavelengths in the maximum absorption peak of deoxy-ERC while for the oxy form a red-shift is noticed. These shifts accompanied an increased affinity of the hemeprotein for oxygen, possibly because of changes in the overall macromolecular conformation. 3) A decrease in the oxygen affinity of erythrocruorin is observed when large amounts of non-specific serum are used. The same effect is observed in the presence of serum albumin, probably as a result of non-specific binding between the albumin and erythrocruorin. 4) The fluorimetric titration of erythrocruorin with anti-ERC Fab fragments results in a decrease in the intrinsic tryptophan fluorescence of the hemeprotein, a response indicative of a modification in the ERC's quaternary structure.
Cardillo
F
F
Departamento de Bioquímica, Universidade Estadual de Campinas, C.P., Brasil.
de Paula
E
E
Oliveira
G R
GR
Marangoni
S
S
Oliveira
B
B
Meirelles
N C
NC
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D002848:Chromatography, DEAE-Cellulose; D006454:Hemoglobins / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007122:Immunoelectrophoresis; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G / Q000276:immunology; D009835:Oligochaeta; D010100:Oxygen / Q000378:metabolism*; D011487:Protein Conformation; D011817:Rabbits; D012709:Serum Albumin / Q000494:pharmacology
D000906:Antibodies; D006454:Hemoglobins; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D012709:Serum Albumin; C064665:erythrocruorin; D010100:Oxygen