<jats:p> <jats:sc>Kim, Ki-han</jats:sc> (Wayne State University, Detroit, Mich.). Isolation and properties of a putrescine-degrading mutant of <jats:italic>Escherichia coli</jats:italic> . J. Bacteriol. <jats:bold>86:</jats:bold> 320–323. 1963.—A mutant was isolated from <jats:italic>Escherchia coli</jats:italic> B which can grow on putrescine as the sole source of carbon and nitrogen. This mutant contains a constitutive putrescine α-ketoglutarate transaminase and can be induced for the enzymes responsible for the conversion of γ-aminobutyraldehyde to succinate. The intracellular putrescine of this mutant could be nearly quantitatively removed by nitrogen starvation. This removal of intracellular putrescine did not damage the reproduction of T <jats:sub>2</jats:sub> in these cells.