Key enzymes of carbohydrate metabolism as targets of the 11.5-kDa Zn(2+)-binding protein (parathymosin).
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.
Brand
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Abteilung Klinische Biochemie, Universität Göttingen, Federal Republic of Germany.
Heinickel
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D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D050260:Carbohydrate Metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002846:Chromatography, Affinity; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D013947:Thymosin / Q000031:analogs & derivatives* / Q000378:metabolism; D015032:Zinc / Q000378:metabolism
D002352:Carrier Proteins; D010455:Peptides; C017800:zinc-binding protein; D013947:Thymosin; C044498:parathymosin alpha; D010732:Phosphofructokinase-1; D005634:Fructose-Bisphosphate Aldolase; D015032:Zinc