A new type of mitogenic factor produced by Streptococcus pyogenes

FEBS Lett. 1992 Aug 10;308(1):30-4. doi: 10.1016/0014-5793(92)81043-l.


A new type of mitogenic factor (protein) was purified from the culture supernatant of a strain of Streptococcus pyogenes by SP-Sephadex C-25 column chromatography, preparative isoelectric focusing and reversed-phase high-performance liquid chromatography. The purified factor, showing marked mitogenic activity in rabbit peripheral blood lymphocytes, gave a single-band staining for protein on SDS-PAGE. The molecular weight of the purified mitogenic factor was determined to be 25,370, which was different from those calculated from reported amino acid sequences deduced from 4 different nucleotide sequences of 3 kinds of streptococcal pyrogenic exotoxins (two SPEAs, SPEB and SPEC). The amino acid sequence of the N-terminal region of the purified mitogenic factor was determined to be Gln-Thr-Gln-Val-Ser-Asn-Asp-Val-Val-Leu-Asn-Asp-Gly-Ala-Ser-Lys-Tyr-Leu- Asn-Glu - Ala-, which was also different from the reported N-terminal sequences deduced from the 4 different nucleotide sequences. These data indicate that this mitogenic factor is distinct from the already described streptococcal pyrogenic exotoxins.

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / analysis
  • Chromatography, High Pressure Liquid
  • Electrophoresis, Polyacrylamide Gel
  • Isoelectric Focusing
  • Mass Spectrometry
  • Mitogens / biosynthesis*
  • Mitogens / genetics
  • Molecular Sequence Data
  • Sequence Homology, Nucleic Acid
  • Streptococcus pyogenes / metabolism*


  • Amino Acids
  • Mitogens