The neurotrophic factor neuroleukin is 90% homologous with phosphohexose isomerase
Abstract
Neuroleukin (NLK) is a protein of relative molecular mass (Mr) 56,000 (56K) secreted by denervated rat muscle1 and found in large amounts in muscle, brain, heart and kidneys2. The protein is a neurotrophic factor for spinal and sensory neurons2 and a lymphokine product of lectin-stimulated T-cells3. It also induces immunoglobulin secretion by human mononuclear cells3. Molecular clones of NLK have been expressed in monkey COS cells and the product was shown to have the same biological and biochemical properties as the extracted protein. NLK is abundant in muscle, brain and kidney, but is active at concentrations of 10-9 to 10-11 M, similar to those for other polypeptide factors. We have cloned the gene for pig muscle phosphohexose isomerase (PHI) (EC 5.3.1.9) which catalyses the conversion of glucose-6-phosphate to f ructose-6-phosphate, an obligatory step in glycolysis, and determined its amino-acid sequence. Surprisingly, it is 90% homologous to the sequence of mouse neuroleukin.
- Publication:
-
Nature
- Pub Date:
- March 1988
- DOI:
- 10.1038/332454a0
- Bibcode:
- 1988Natur.332..454C