Polyproline tetramer organizing peptides in fetal bovine serum acetylcholinesterase

Kevser Biberoglu, Lawrence M. Schopfer, Ashima Saxena, Ozden Tacal, Oksana Lockridge

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Acetylcholinesterase (AChE) in the serum of fetal cow is a tetramer. The related enzyme, butyrylcholinesterase (BChE), in the sera of humans and horse requires polyproline peptides for assembly into tetramers. Our goal was to determine whether soluble tetrameric AChE includes tetramer organizing peptides in its structure. Fetal bovine serum AChE was denatured by boiling to release non-covalently bound peptides. Bulk protein was separated from peptides by filtration and by high performance liquid chromatography. Peptide mass and amino acid sequence of the released peptides were determined by MALDI-TOF-TOF and LTQ-Orbitrap mass spectrometry. Twenty polyproline peptides, divided into 5 families, were identified. The longest peptide contained 25 consecutive prolines and no other amino acid. Other polyproline peptides included one non-proline amino acid, for example serine at the C-terminus of 20 prolines. A search of the mammalian proteome database suggested that this assortment of polyproline peptides originated from at least 5 different precursor proteins, none of which were the ColQ or PRiMA of membrane-anchored AChE. To date, AChE and BChE are the only proteins known that include polyproline tetramer organizing peptides in their tetrameric structure.

Original languageEnglish (US)
Pages (from-to)745-753
Number of pages9
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Issue number4
StatePublished - Apr 2013


  • Fetal bovine serum acetylcholinesterase
  • Mass spectrometry
  • PAGE gel electrophoresis
  • Polyproline peptide
  • Tetramer organization

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biophysics
  • Biochemistry
  • Molecular Biology


Dive into the research topics of 'Polyproline tetramer organizing peptides in fetal bovine serum acetylcholinesterase'. Together they form a unique fingerprint.

Cite this