Introduction

Human prostatic acid phosphatase (PAP) is a homodimeric glycoprotein secreted by prostate gland. Receptor cErbB2, exhibiting protein tyrosine kinase activity and inactivated by PAP-catalysed dephosphorylation of phosphotyrosine residues, seems to be the physiological substrate of cellular PAP, but LPA (dephosphorylated by PAP) and semenogelins (both: dephosphorylated and proteolysed by PAP) of seminal fluid PAP.

Human PAP belongs to allosteric enzymes: it exhibits positive cooperativity in substrate binding, the extent of cooperativity grows with the increase of enzyme concentration and depends on the nature of substrate molecule [1,2]. Ligand-induced association-dissociation equilibrium of the active oligomeric species (monomer-dimer-tetramer-oligomers) was stated [3]. Cooperative properties of PAP are dependent on both: quaternary and tertiary structure changes [4].

Aim

• Further studies on regulation of PAP catalytic activity by enzyme concentration changes
• Studies on inhibition of allosteric PAP by L(+)-tartrate and vanadate, used as drugs

Results

• PAP exhibits positive cooperativity in substrate binding when pNPP is used as hydrolysis substrate and the extent of cooperativity grows when PAP concentration is increased
• L(+)-tartrate and vanadate are both non-linear competitive inhibitors of PAP-catalysed hydrolysis. Positive cooperativity in substrate binding exhibited by PAP is diminished by both inhibitors studied, when pNPP and FP are used as substrates

References

[1] Luchter-Wasylewska E (2001) Biochim. Biophys. Acta 1548, 257-264

[2] Luchter-Wasylewska E & Iciek M (2004) J. Coll. Interface Sci. 273, 632-637

[3] Luchter-Wasylewska E, Wasylewski M & Röhm KH (2003) J. Protein Chem. 22, 243-247

[4] Luchter-Wasylewska E (2004) Regulation of human prostatic acid phosphatase activity. Jagiell. Univ. Press

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/10836 must be provided.