Inhibitory Activity Is Due to IFS

<p>The NAD-glycohydrolase activities of a mixture of JRS4 supernatant (as a source of SPN) and cytoplasmic extracts prepared from several derivatives of JRS4 SPN⁻ mutant SPN1 are shown. Lanes include SPN⁻ mutant itself (Parent), a derivative of SPN⁻ mutant with an in-frame deletion in <i>ifs</i> (IFS⁻), a sibling of the SPN⁻ IFS⁻ deletion mutant that reverted to wild-type <i>ifs</i> (IFS⁺ Rev.), the SPN⁻ IFS⁻ deletion mutant containing a plasmid-encoded HA-tagged version of IFS (IFS⁻ pIFS-HA), and the pABG5 plasmid vector lacking <i>ifs</i> (IFS⁻ Vector). Asterisk indicates that the level of NAD-glycohydrolase activity was below the limit of detection of 50 pmol/min. Data represent the mean ± standard error of the mean derived from three independent experiments.