The place of human gamma-trace (cystatin C) amongst the cysteine proteinase inhibitors

Biochem Biophys Res Commun. 1984 Apr 30;120(2):631-6. doi: 10.1016/0006-291x(84)91302-0.


Native gamma-trace, a small basic protein present in high concentration in cerebrospinal fluid, semen and neuroendocrine cells, but of unknown biological function, is shown to be a potent inhibitor of the cysteine proteinases papain, ficin, and human cathepsins B, H and L. It proves to be the tightest -binding protein inhibitor of cathepsin B so far discovered. The name cystatin C is proposed for gamma-trace to reflect the many similarities in activity and structure to chicken egg-white cystatin and mammalian cystatins A and B. The inhibition constants of cystatin C, taken together with its widespread distribution in human tissues and extracellular fluids, suggest that a physiological function could well be the regulation of cysteine proteinase activity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cathepsins / antagonists & inhibitors
  • Cystatin C
  • Cystatins*
  • Drug Stability
  • Epitopes / immunology
  • Ficain / antagonists & inhibitors
  • Humans
  • Kinetics
  • Papain / antagonists & inhibitors
  • Protease Inhibitors
  • Proteins / immunology
  • Proteins / pharmacology*


  • CST3 protein, human
  • Cystatin C
  • Cystatins
  • Epitopes
  • Protease Inhibitors
  • Proteins
  • Cathepsins
  • Papain
  • Ficain