Key enzymes of carbohydrate metabolism as targets of the 11.5-kDa Zn(2+)-binding protein (parathymosin)

J Biol Chem. 1991 Nov 5;266(31):20984-9.

Abstract

The 11.5-kDa Zn(2+)-binding protein (ZnBP) was covalently linked to Sepharose. Affinity chromatography with a cytosolic subfraction from liver resulted in purification of a predominant 38-kDa protein. In comparable experiments with brain cytosol a 39-kDa protein was enriched. The ZnBP-protein interactions were zinc-specific. Both proteins were identified as fructose-1,6-bisphosphate aldolase. Experiments with crude cytosol showed zinc-specific interaction of additional enzymes involved in carbohydrate metabolism. From liver cytosol greater than 90% of the following enzymes were specifically retained: aldolase, phosphofructokinase-1, hexokinase/glucokinase, glucose-6-phosphate dehydrogenase, glycerol-3-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and fructose-1,6-bisphosphatase. Glucose-6-phosphate isomerase, phosphoglycerate kinase, enolase, lactate dehydrogenase, and most of triosephosphate isomerase remained unbound. From L-type pyruvate kinase only the phosphorylated form seems to interact with ZnBP. Using brain cytosol hexokinase, phosphofructokinase-1, and aldolase were completely bound to the affinity column, whereas glucose-6-phosphate isomerase, phosphoglycerate kinase, enolase, lactate dehydrogenase, pyruvate kinase, and most of triose-phosphate isomerase remained unbound. The behavior of glucose-6-phosphate dehydrogenase and glycerol-3-phosphate dehydrogenase from this tissue could not be followed. A possible function of ZnBP in supramolecular organization of carbohydrate metabolism is proposed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Brain / metabolism
  • Carbohydrate Metabolism
  • Carrier Proteins / metabolism*
  • Chromatography, Affinity
  • Fructose-Bisphosphate Aldolase / metabolism*
  • Liver / metabolism
  • Molecular Sequence Data
  • Peptides / chemistry
  • Phosphofructokinase-1 / metabolism*
  • Protein Binding
  • Rats
  • Thymosin / analogs & derivatives*
  • Thymosin / metabolism
  • Zinc / metabolism

Substances

  • Carrier Proteins
  • Peptides
  • zinc-binding protein
  • Thymosin
  • parathymosin alpha
  • Phosphofructokinase-1
  • Fructose-Bisphosphate Aldolase
  • Zinc