Calcium transport by ionophorous peptides in dog and human lymphocytes detected by quin-2 fluorescence

Biochem Biophys Res Commun. 1986 Jan 29;134(2):731-5. doi: 10.1016/s0006-291x(86)80481-8.

Abstract

Synthetic peptides of structure cyclo(Glu(OBz)-Sar-Gly-(N-R)Gly)2 (I), electrogenic Ca2+-selective carriers in phospholipid vesicle membranes, are shown to mediate the uptake of Ca2+ ions into the cytoplasm of dog and human lymphocytes. Ca2+ transport by DECYL-2E (I, R = n-decyl) - monitored by measurements of the fluorescence of an intracellular dye, quin-2 - occurred at a rate comparable to that produced by electroneutral Ca2+ ionophores ionomycin and Br-A23187. Fluorescence quenching experiments using Mn2+ suggested a greater selectivity by DECYL-2E for Ca2+/Mn2+ vs. the other two ionophores. The result that Ca2+ ions can traverse biological membranes bound in a neutral cavity consisting exclusively of peptide carbonyl ligands may imply the functional significance of binding sites of similar structures in membrane transport proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoquinolines
  • Animals
  • Biological Transport
  • Calcium / metabolism*
  • Dogs
  • Extracellular Matrix / metabolism
  • Humans
  • Ionophores / metabolism*
  • Lymphocytes / metabolism*
  • Manganese / metabolism
  • Peptides, Cyclic / metabolism*

Substances

  • Aminoquinolines
  • Ionophores
  • Peptides, Cyclic
  • Manganese
  • cyclo(Glu(O-benzyl)-Sar-Gly-(N-n-decyl)Gly)2
  • Quin2-acetoxymethyl ester
  • Calcium