Degradation of serine-containing oligopeptides by Peptostreptococcus micros ATCC 33270

Oral Microbiol Immunol. 2007 Dec;22(6):381-3. doi: 10.1111/j.1399-302X.2007.00374.x.

Abstract

Background/aims: Microorganisms of Peptostreptococcus micros are asaccharolytic, anaerobic gram-positive cocci that are frequently isolated from human oral sites such as periodontal pockets. Preliminary study showed that several amino acids, including serine, enhanced slightly the growth of P. micros. Therefore, we investigated the degradation of serine and serine-containing oligopeptides.

Methods: Metabolic end products were determined with high-performance liquid chromatography. The related enzymatic activities in cell-free extract were also assayed.

Results: Washed P. micros degraded serine-tripeptides (Ser-Ser-Ser), and produced formate, pyruvate, acetate, and ammonia. They also degraded serinyl-tyrosine (Ser-Tyr) to the same products. Related enzymatic activities, such as serine dehydratase, pyruvate formate-lyase, formate dehydrogenase, pyruvate oxidoreductase, phosphate acetyltransferase, and acetate kinase, were detected in the cell-free extract, indicating that the organisms produced ATP in the serine metabolism.

Conclusion: P. micros utilized serine-containing oligopeptides as exogenous metabolic substrates rather than serine itself, and degraded Ser-Ser-Ser and Ser-Tyr to formate, pyruvate, acetate, and ammonia with ATP generation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetate Kinase
  • Acetates / metabolism
  • Acetyltransferases
  • Adenosine Triphosphate / biosynthesis
  • Ammonia / metabolism
  • Formate Dehydrogenases
  • Formates / metabolism
  • Humans
  • L-Serine Dehydratase / metabolism
  • Oligopeptides / metabolism*
  • Peptostreptococcus / enzymology
  • Peptostreptococcus / metabolism*
  • Phosphate Acetyltransferase
  • Pyruvate Synthase
  • Pyruvic Acid / metabolism
  • Serine / metabolism*
  • Tyrosine / metabolism

Substances

  • Acetates
  • Formates
  • Oligopeptides
  • formic acid
  • Tyrosine
  • Serine
  • Ammonia
  • Pyruvic Acid
  • Adenosine Triphosphate
  • Formate Dehydrogenases
  • Pyruvate Synthase
  • Acetyltransferases
  • formate C-acetyltransferase
  • Phosphate Acetyltransferase
  • Acetate Kinase
  • L-Serine Dehydratase