TABLE 3.

pH optima, cofactor specificities, and activities of enzymes involved in CHAM degradation by cell extracts of B. oxydans IH-35A after growth on CHAM, CHnone, and succinate^a

Enzymeb	pH opti-mumc	Cosubstrate specificity	Activity (μmol min−1 [mg of protein]−1)
			CHAM-grown cells	CHnone-grown cells	Succinate-grown cells
CHAM oxidase	7.0–7.5	None	0.26	<0.01	<0.01
CHnone monooxy-genase	9.0–9.5	NADPH	0.75	0.83	<0.01
6-Hexanolactone hydrolase	7.2–7.4	None	15.63	14.27	<0.01
6-Hydroxyhexanoate dehydrogenase	7.0–7.5	NADP	0.02	0.02	<0.01

^aThe data are averages of the data from three different experiments. 

^bCHAM oxidase activity was assayed by measuring the formation of NH₃ accompanying the degradation of CHAM. CHnone monooxygenase activity was assayed by monitoring the CHnone-dependent oxidation of NADPH at 340 nm by the method of Norris and Trudgill (9). 6-Hexanolactone hydrolase activity was assayed by the method of Cain (2). 6-Hydroxyhexanoate dehydrogenase activity was assayed by measuring the increase in absorbance at 340 nm due to NAD⁺ reduction by using the method of Donoghue and Trudgill (4). 

^cThe effects of pH on enzyme-catalyzed reactions were determined by using five different buffer mixtures, each at a concentration of 20 mM, covering the pH range from 4 to 11. The buffers used were sodium acetate, sodium citrate, phosphate, Tris-HCl, and glycine-NaOH.