A caged sperm-activating peptide that has a photocleavable protecting group on the backbone amide

FEBS Lett. 2002 Aug 14;525(1-3):20-4. doi: 10.1016/s0014-5793(02)03000-4.


A backbone-caged sperm-activating peptide (caged speract) that has a 2-nitrobenzyl group at a backbone amide and a vastly reduced affinity for its receptor (IC50=950 nM) was synthesized. UV irradiation of caged speract photocleaves the 2-nitrobenzyl group (tau1/2=26 micros), restoring its affinity (IC50=0.67 nM) and ability to increase sperm intracellular pH and Ca2+, as intact speract. Backbone caging of the biological activity was more efficient than side chain caging, which adds a nitrobenzyl group on the peptide side chain. The backbone caging strategy described can be used as a general procedure to cage biologically active peptides, which have no side chain for introduction of a caging group.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding, Competitive
  • Calcium / metabolism
  • Fluorescent Dyes
  • Hydrogen-Ion Concentration
  • Intracellular Fluid / metabolism
  • Male
  • Molecular Sequence Data
  • Oligopeptides / chemistry*
  • Oligopeptides / pharmacokinetics
  • Oligopeptides / pharmacology*
  • Peptides / chemical synthesis
  • Peptides / pharmacokinetics
  • Peptides / radiation effects*
  • Photolysis
  • Protein Engineering
  • Sea Urchins
  • Spectrometry, Fluorescence
  • Spectrophotometry
  • Spermatozoa / drug effects*
  • Spermatozoa / metabolism
  • Spermatozoa / radiation effects
  • Ultraviolet Rays


  • Fluorescent Dyes
  • Oligopeptides
  • Peptides
  • speract
  • Calcium