Leucine Aminopeptidase in Eggs of the Soybean Cyst Nematode Heterodera glycines

Authors

  • Paul M. Tefft
  • Leon W. Bone

Abstract

Supernatant from a sonicated macerate of eggs of Heteroderaglycines hydrolyzed L-leucine[beta]-naphthylamide and L-leucine 7-amido-4-methylcoumarin. Rate of substrate hydrolysis was influenced by pH and increased with the duration of incubation. A Michaelis-Menten constant of 0.15 mM was obtained. Rate of substrate hydrolysis was decreased by freezing egg supernatant for 26 days or heating above 60 C for 5 minutes. When egg supernatant was incubated with six different substrates, L-leucine[beta]-naphthylamide was hydrolyzed most readily and L-valine[beta]-naphthylamide the least readily. The rate of substrate hydrolysis by egg supernatant was not increased by pretreatment of eggs with 3 mM zinc chloride for up to 14 days. Key words: biochemistry, egg hatching, enzyme, Glycine max, soybean, nematode eggs.

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Published

1985-07-15

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Section

Articles