Neuraminidase in Mammalian Brain

Abstract

CONTAMINATION of serum with neuraminidase-producing bacterial cells promptly produces changes in the electrophoretic pattern. The mobility (surface charge) of the α₁-globulins (orosomucoid and α₁-antitrypsin), of some α₂-globulins (for example, haptoglobin) and of the β₁-globulin, transferrin, decreases on release of sialic acid from the molecular surface¹. Vulpé² has published electrophoretic protein patterns of rabbit sera before and during development of experimental encephalomyelitis induced by injections of a brain suspension in combination with Freund's adjuvant. The changes in serum presented are similar to those produced by neuraminidase. Furthermore, the transferrin of human cerebrospinal fluid is electrophoretically heterogeneous³, indicating that part of it has lower sialic acid content than the most common transferrin type of Caucasians. These two observations prompted the present investigation of mammalian brain for neuraminidase. This enzyme is common among microorganisms, and has been found in chick-embryo chorioallantois but not in mammalian tissue⁴.