Double labeled proteins

Double-labeled proteins from rat liver cytosol ( C in long-lived, in short-liv J proteins after in vivo labeling) have been used as substrates for proteinases in vitro. The differences in the degradation rates of short-lived and long-lived proteins in vitro by different proteinases in the presence or absence of different effectors enabled conclusions to be drawn concerning their role in in vivo turnover. The main activity of lysosomal proteinases at pH values of 6.1 and 6.9 was found to be caused by thiol proteinases which decompose short-liv l cytosol proteins preferentially. Autolysis of double-labeled cell fractions showed a remarkably faster breakdown of short-lived substrate proteins only in the soluble part of lysosomes >. 

Zhang, S. M., Wu, J., and Gorenstein, D. G. (1996) Double-WURST decoupling for N-15- and C-13-double-labeled proteins in a high magnetic field. J. Magn. Reson. Series A 123(2), 181-187. 

Szyperski T, Wider G, Bushweller JH, Wiithrich K (1993) 3D 13 C-15 N-heteronuclear two-spin coherence spectroscopy for polypeptide backbone assignments in 13 C-15 N-double-labeled proteins. J Biomol NMR 3 127-132... 

Non-Specific Double Labels Protein Turnover in Soybean Leaves... 

Kover and Batta have demonstrated the G-BIRD " decoupled TROSY sequences for labelled proteins that allow accurate measurements of /c n and Vhn couplings. For the measurement of the same couplings in double labelled proteins and for the measurement of the Vhc couplings Hoshino and Otting have proposed a generalized TROSY version, the sensitivity enhanced [ N H]-double-TROSY experiment. 

Phase incremented double adiabatic decoupling for 13C- and 15N-labelled proteins... 

Fig. 1. Double label immunohistochemistry on rai liver. An acetone-fixed rat liver section was incubated with a polyclonal antiserum raised in rabbit to a hepa-tocyte cell surface protein (courtesy of Dr. S. Stamatoglou) and a mouse monoclonal antibody against a bile duct specific cytokeratin (courtesy of Dr. E. B. Lane). The hepatocyte protein was localized by use of a secondary peroxidase-conjugated antibody resulting in a red/brown product (thin arrow). The bile duct cytokeratin was identified by using an alkaline phosphatase-conjugated secondary antibody giving a blue color (thick arrow).

Kainosho M, Tsuji T, Assignment of the three methionyl carbonyl carbon resonances in Streptomyces subtilisin inhibitor by a carbon-13 and nitrogen-15 double-labeling technique. A new strategy for structural studies of proteins in solution, Biochemistry, 21 6273-6279, 1982. 

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