Initiates the rapid degradation of small, acid-soluble proteins during spore germination. Endopeptidase action with P4 Glu or Asp, P1 preferably Glu > Asp, P1' hydrophobic and P2' Ala. Homotetramer. GPR transcription occurs during sporulation in forespore first by sigma-F and then by sigma-G. Autoproteolytically processed. The inactive tetrameric zymogen termed p46 autoprocesses to a smaller form termed p41, which is active only during spore germination. Belongs to the peptidase A25 family.