Ganglioside‐Modulated Proteolysis by Ca2+‐Activated Neutral Proteinase (CANP): A Role of Glycoconjugates in CANP Regulation

Publisher Website
Google Scholar
Abstract
We examined ganglioside modulation of the activity of the millimolar Ca2+‐sensitive form (mCANP) of calcium‐activated neutral proteinase (CANP), which is enriched in myelin, from brain. GM1, GD1a, GT1a, GM2, and GM4 produced a concentration‐dependent increase of mCANP activity. GD1a stimulated the greatest increase of enzyme activity (107%), followed by GT1a, whereas GD1b was inhibitory (56%). GM1, GM2, and GM4 stimulated but less so than GD1a and GT1a. Free N‐acetylneuraminic acid, asialo‐GM1, GM3, and a ganglioside mixture containing GM1, GD3, GD1a, and GD1b had no effect. The ganglioside‐mediated modulation was not affected by trifluoperazine and chlorpromazine (phospholipid‐binding antagonists). The mCANP Ca2+ requirement was significantly reduced in the presence of stimulatory gangliosides, and this increased sensitivity varied (10–50‐fold) with ganglioside structure. Gangliosides may interact with membrane mCANP and modulate its proteolytic action.