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. 1982 Oct;79(19):6084–6088. doi: 10.1073/pnas.79.19.6084

Isolation, characterization, and purification to homogeneity of a rat brain protein (GABA-modulin).

A Guidotti, D R Konkel, B Ebstein, M G Corda, B C Wise, H Krutzsch, J L Meek, E Costa
PMCID: PMC347057  PMID: 6964401

Abstract

gamma-Aminobutyric acid (GABA)-modulin is a brain neuropeptide that appears to modulate specific high-affinity (20 nM) GABA recognition sites in brain. When added to crude synaptic membranes this peptide inhibits binding of [3H]GABA to the high-affinity site and prevents facilitation of [3H]diazepam binding elicited by GABA. GABA-modulin has been purified to homogeneity by ammonium sulfate precipitation, gel chromatography, and reverse-phase HPLC. Homogeneity was confirmed by a variety of means, including chromatography under four different HPLC conditions, two different polyacrylamide gel electrophoreses, and end group analysis. Purified GABA-modulin contains approximately 126 amino acids and has a molecular weight of 16,500. The GABA-modulin molecule contains an abundance of hydrophilic basic residues, and neither cysteine nor GABA is present. End group analyses of GABA-modulin showed that histidine is the free COOH terminus and the NH2 terminus is blocked. GABA-modulin specifically blocked both [3H]GABA binding to synaptic membranes (IC50, 0.5 microM) and GABA-stimulated [3H]diazepam binding; the binding of [3H]GABA to low-affinity sites was not affected.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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