Purification and characterization of a hemocyanin (Hemo1) with potential lignin-modification activities from the wood-feeding termite, Coptotermes formosanus Shiraki

Appl Biochem Biotechnol. 2015 Jan;175(2):687-97. doi: 10.1007/s12010-014-1326-z. Epub 2014 Oct 24.

Abstract

Coptotermes formosanus Shiraki is a well-known wood-feeding termite, which can degrade not only cellulose and hemicellulose polysaccharides, but also some aromatic lignin polymers with its enzyme complex to the woody biomass. In this study, a very abundant protein was discovered and purified, using a three-step column chromatography procedure, from the tissue homogenate of the salivary glands and the gut of C. formosanus. Mass spectrometric analysis and the following peptide searching against the mRNA database toward this termite species indicated that the novel protein was a hemocyanin enzyme, termed as Hemo1, which further exhibited a strong oxidase activity in the substrate bioassays toward ABTS [2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)], as well as other aromatic analogues, such as catechol and veratryl alcohols. This oxidative protein was an acid-favored enzyme with a molecular weight at 82 kDa, and highly active at 80 °C. These findings indicated that the novel protein, hemocyanin, discovered from the gut system of C. formosanus, might be an important ligninolytic enzyme involved in the biomass pretreatment processing, which will potentially enhance the digestibility and utilization of biomass polysaccharides in termite digestive systems.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Benzothiazoles / chemistry
  • Benzyl Alcohols / chemistry
  • Catechols / chemistry
  • Enzyme Stability
  • Gastrointestinal Tract / chemistry
  • Gastrointestinal Tract / enzymology
  • Hemocyanins / chemistry*
  • Hemocyanins / isolation & purification
  • Hot Temperature
  • Insect Proteins / chemistry*
  • Insect Proteins / isolation & purification
  • Isoptera / chemistry*
  • Isoptera / enzymology
  • Kinetics
  • Lignin / chemistry*
  • Lignin / metabolism
  • Molecular Sequence Data
  • Molecular Weight
  • Oxidoreductases / chemistry*
  • Oxidoreductases / isolation & purification
  • Peptide Mapping
  • Salivary Glands / chemistry
  • Salivary Glands / enzymology
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Substrate Specificity
  • Sulfonic Acids / chemistry
  • Wood / metabolism

Substances

  • Benzothiazoles
  • Benzyl Alcohols
  • Catechols
  • Insect Proteins
  • Sulfonic Acids
  • 2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid
  • Lignin
  • Hemocyanins
  • Oxidoreductases
  • catechol
  • veratryl alcohol