Individual recombinant thyroglobulin type-1 domains are substrates for lysosomal cysteine proteinases.
Thyroglobulin contains 11 repeats of a motif called thyroglobulin type-1 domain that show sequence similarity to some proteins exhibiting inhibitory activity against cysteine proteinases. Here we report that thyroglobulin decreases the activity of cathepsins B, H, L, and papain. To examine the possible involvement of particular type-1 domains in that decrease of activity, some individual thyroglobulin type-1 domains were expressed in E. coli. These recombinant domains proved to be substrates for cathepsins B, H, L, and papain instead of inhibitors. The cleavage points with cathepsins B and L on the second and the fourth domains were determined. The possible reasons for degradation are discussed.
Pungercic
Galina
G
Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, SI-1 000 Ljubljana, Slovenia.
Dolenc
Iztok
I
Dolinar
Marko
M
Bevec
Tadeja
T
Jenko
Sasa
S
Kolaric
Sasa
S
Turk
Vito
V
D000595:Amino Acid Sequence; D000818:Animals; D002403:Cathepsins / Q000378:metabolism; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008247:Lysosomes / Q000201:enzymology*; D008969:Molecular Sequence Data; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013954:Thyroglobulin / Q000737:chemistry / Q000378:metabolism*
D011994:Recombinant Proteins; D013954:Thyroglobulin; D002403:Cathepsins; D003546:Cysteine Endopeptidases