Biochemical Characterization of 60S Acidic Ribosomal P Proteins from Porcine Liver and the Inhibition of Their Immunocomplex Formation with Sera from Systemic Lupus Erythematosus (SLE) Patients by Glycyrrhizin in Vitro

• Published in: Biological & pharmaceutical bulletin 2000/01/01, Vol.23(1), pp.27-32
• Main Authors: MAEKAWA, Toshiro, KOSUGE, Seiji, KARINO, Atsushi, OKANO, Tetsuro, ITO, Junko, MUNAKATA, Hiroshi, OHTSUKI, Kenzo
• Format: Article
• Language: English
• Subjects: 60S acidic ribosomal P protein; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; anti-oxidant compound; Antibody Specificity; Antigen-Antibody Complex - blood; Antioxidants - pharmacology; Autoantibodies - immunology; Autoantibodies - metabolism; Biological and medical sciences; Casein Kinase II; casein kinase II inhibitor; Chromatography, Affinity; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods; Glycyrrhizic Acid - pharmacology; glycyrrhizin; glycyrrhizin-binding protein; Humans; Liver - chemistry; Liver - enzymology; Lupus Erythematosus, Systemic - blood; Lupus Erythematosus, Systemic - immunology; Molecular Sequence Data; Phosphoproteins - antagonists & inhibitors; Phosphoproteins - blood; Phosphoproteins - immunology; Phosphoproteins - isolation & purification; Phosphorylation - drug effects; Protein-Serine-Threonine Kinases - antagonists & inhibitors; Protein-Serine-Threonine Kinases - isolation & purification; Protein-Serine-Threonine Kinases - metabolism; Proteins; Ribosomal Proteins - antagonists & inhibitors; Ribosomal Proteins - blood; Ribosomal Proteins - immunology; Ribosomal Proteins - isolation & purification; Swine
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.23.27

The three casein kinase II (CK-II) phosphate acceptors (p35, p17 and p15) in the Superdex CK-II fraction prepared from a 1.5 M NaCl extract of porcine liver were selectively purified by glycyrrhizin (GL)-affinity column chromatography (HPLC) as a heterocomplex associated with CK-II. Determination of the N-terminal amino acid sequences and immunological tests confirmed that these three CK-II phosphate acceptors belong to the family of 60S acidic ribosomal proteins (P0, P1 and P2). Three polyphenol-containing anti-oxidant compounds [catechin, epigallocatechin gallate (EGCG) and quercetin] inhibited CK-II activity (phosphorylation of these ribosomal P proteins) in a dose-dependent manner in vitro. Quercetin (ID50n=approx. 50 nM) was found to be an effective CK-II inhibitor. In contrast, CK-II activity was significantly stimulated by lower doses (0.3-3 μM) of GL, but was inhibited at high doses above 30 μM. As expected, GL at high doses above 200 μM inhibited the immunocomplex formation of 60S acidic ribosomal P proteins with their specific antibodies in the sera from patients with systemic lupus erythematosus (SLE). These results suggest that (i) a GL-affinity column is useful for effective purification of 60S acidic ribosomal P proteins from various mammalian cells as a heterocomplex associated with CK-II; and (ii) a relative high dose of GL may prevent the immunocomplex formation of 60S acidic ribosomal P proteins with their specific antibodies in the sera of SLE patients.