7.4.2.1	acetaminophen causes degradation of the enzyme	
7.4.2.1	ATP-binding subunit HisP with a carboxy-terminal extension of 8 amino acids is stable to freezing and thawing	
7.4.2.1	preparation diluted to 0.7 mg/ml protein and 4% glycerol is stable at 0°C for at least 1 h