| abstract |
A new homogeneous cytosolic binding protein (FKBP-14.6 immunophilin) having a molecular weight of about 14.6 kDa (calculated from its amino acid composition), reversibly binds the immunosuppressive drugs FK-506, rapamycin or chemically related compounds, but not cyclosporine. The FKBP-14.6 protein has a pI of 6.5-7.5, and the (partial) N-terminal amino acid sequence: NH2-Lys-Leu-Pro-Tyr-Glu-Leu-Lys-X-Asn-Val-Lys-Ala-Phe-X-X-Lys-Val- (where X is undefined), and partial internal amino acid sequences -Val-Leu-Asp-Thr-Ala-Tyr-Glu-Tyr-Gly-Ala-Glu-Ala-Leu-Glu-, -Glu-Phe-Thr-Pro-Val-Phe-Gln-Ala-X-Phe- and -Ser-Leu-Val-Pro-Leu-Val-Gly-X-Lys- (where X is undefined). This N-terminal amino acid sequence exhibits no homology to FKBP-12 or membrane-associated FKBP-13. THe FKBP-14.6 is isolated from the cytosol of mammalian tissues, preferably calf thymus, and can be used in diagnostic and purification procedures involving FK-506 and rapamycin-type immunosuppressant drugs. |