Activation of pro-phenoloxidase by the activating enzyme of the silkworm, Bombyx mori

  • Ashida M
  • Dohke K
  • 5

    Readers

    Mendeley users who have this article in their library.
  • 117

    Citations

    Citations of this article.

Abstract

The activation reaction of prophenoloxidase was analyzed using a homogeneous pro-enzyme preparation and highly purified pro-phenoloxidase activating enzyme (abbreviated as PPAE) obtained from silkworm larvae. The activation of pro-enzyme by PPAE results in release of a peptide having a molecular weight of about 5000 calculated from its amino acid composition and the difference between the molecular weights of the pro-enzyme and phenoloxidase. PPAE seems to be a highly specific enzyme capable of limited proteolysis, since no further degradation of phenoloxidase or release of any other peptide could be detected. Phenoloxidases having different kinetic properties and substrate specificities were obtained depending on the pH at which activation took place, although the molecular weights of phenoloxidase determined by sodium dodecylsulphate-electrophoresis were the same irrespective of the operating pH. This suggests that a process subsequent to peptide bond cleavage in the activation reaction is influenced by pH, resulting in phenoloxidases with different properties. Phenoloxidase seems to be present as progressively higher molecular weight aggregates. The enzyme is bound strongly to foreign surfaces such as glass, DEAE-cellulose and hydroxyapatite, from which much of the enzyme activity cannot be eluted by high NaCl or phosphate concentration. This may be important in relation to the intracellular binding and occurrence of multiple forms of phenoloxidase. © 1980.

Author-supplied keywords

  • activation of pro-phenoloxidase
  • limited proteolysis
  • phenoloxidase
  • tyrosinase

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Masaaki Ashida

  • Kenjiro Dohke

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free