Presence of Ca(2+)-sensitive and -insensitive SM22 alpha isoproteins in bovine aorta

• Published in: Biochemical and biophysical research communications Vol. 229; no. 1; pp. 225 - 230
• Main Authors: Shishibori, T, Yamashita, K, Bandoh, J, Oyama, Y, Kobayashi, R
• Format: Journal Article
• Language: English
• Published: United States 04-12-1996
• Subjects: Amino Acid Sequence; Animals; Antibody Specificity; Aorta - chemistry; Calcium - pharmacology; Cattle; Cross Reactions; Microfilament Proteins; Molecular Sequence Data; Molecular Weight; Muscle Proteins - classification; Muscle Proteins - drug effects; Muscle Proteins - immunology; Muscle Proteins - isolation & purification; Muscle, Smooth, Vascular - chemistry; Peptide Mapping; Sequence Analysis; Tissue Distribution
• ISSN: 0006-291X
• DOI: 10.1006/bbrc.1996.1784

Two proteins (25- and 22-kDa) that cross-react with anti-gizzard SM22 alpha antibody were isolated from bovine aorta. The former, identical to a SM22 alpha homolog reported previously (Kobayashi, R., Kubota, T., and Hidaka, H. (1994) Biochem. Biophys. Res. Commun. 198, 1275-1280), associates with the membrane fraction in the presence of Ca2+ and dissociates in the presence of EGTA, while the latter is insensitive to Ca2+. Peptide mapping and partial sequence analysis revealed that the 22-kDa protein is an isoform of the 25-kDa protein, without 22 amino acid residues from the C-terminus. Immunological analysis of the tissue distribution of these proteins showed that the 25-kDa protein exists in lung and spleen besides aorta, while the 22-kDa protein occurs specifically in the aorta and spleen.