SERUM CLASS-M IMMUNOGLOBULINS OF PATIENTS WITH LUPUS-ERYTHEMATOSUS EFFICIENTLY CLEAVE RNA

A procedure for isolating homogeneous RNA-hydrolyzing IgM antibodies ( AB) from the blood of patients with systemic lupus erythematosus was e laborated. Their interaction with poly- and oligoribonucleotides was a nalyzed. The ability to hydrolyze RNA proved to be an intrinsic proper ty of IgM. Their specific activity was higher than that of IgG. The cl eavage rate decreased with RNA > poly(U) greater than or equal to poly (A) much greater than poly(C) and was about two orders of magnitude hi gher with RNA than with DNA. The optimal pH and concentrations of mono - and divalent metal ions were determined. Kinetic and thermodynamic p arameters of the hydrolysis were estimated with r(pA)(13) and d(pA)(13 ).