obsolete holin true GO:0015176 molecular_function This term was made obsolete because it represents a class of gene products. holin OBSOLETE. Primary function of holins appears to be transport of murein hydrolases across the cytoplasmic membrane to the cell wall of bacteria, where these enzymes hydrolyze the cell wall polymer as a prelude to cell lysis. When chromosomally encoded, these enzymes are therefore autolysins. Holins may also facilitate leakage of electrolytes and nutrients from the cell cytoplasm, thereby promoting cell death. Some catalyze export of nucleases. cytolysis