Estudos bioquimicos e fisicos de hemoglobina extracelular de Glossoscolex paulistus (Oligochaeta)

AUTOR(ES)
DATA DE PUBLICAÇÃO

1988

RESUMO

Glossoscolex paulistus (Oligochaeta, Glossoscolecidae) is an earthworm which dwells in limestone regions in São Paulo State, and has a giant extracellular hemeprotein that occurs in the blood. This type of respiratory pigment is called erythrocruorin, and is examined with the aid of electronic microscopy as two hexagonal superimposed disks, each one having six subunits and a central cavity. This thesis studies the affinity of erythrocruorin with oxygen in the presence of the divalent cation magnesium: an increase of affinity and cooperativity is observed. The sedimentation coefficient was found to be 58 S, and the molecular weight approximately 3.23 x 106 Da. The minimum molecular weight determined, 25,250 Da, was relatively high compared with those of tetrameric hemoglobins and mioglobins, thus suggesting the presence of subunits not carrying a heme group as is the case with other erithrocruorins. Small angle X-ray scattering experiments led to the determination of low resolution dimensional parameters such as the radius of giration (11.4 nm) and maximum molecular dimension (27 nm).

ASSUNTO(S)

hemoglobina anelideo bioquimica

ACESSO AO ARTIGO

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