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Erythrocruorin of Glossoscolex paulistus (Oligochaeta, Glossoscolecidae): Modulation of oxygen affinity by specific antibodies
Author(s) -
Cardillo F.,
de Paula E.,
Oliveira G. R.,
Marangoni S.,
Oliveira B.,
Meirelles N. C.
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700201521
Subject(s) - chemistry , hemeprotein , oxygen , antiserum , tryptophan , fluorescence , protein quaternary structure , titration , protein subunit , biophysics , crystallography , antibody , biochemistry , heme , enzyme , inorganic chemistry , organic chemistry , optics , amino acid , immunology , biology , physics , gene
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 form 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.