TABLE 2.

Amount of substrate depleted 5 min after initiation of reaction with various enzymes

Substrate	nmol of substrate depleted or metabolite produced/1.2 nmol of enzymea
	ht-αP6βP6 ISPBPH	ht-αP6βLB400 ISPBPH	ht-αP6βB-356 ISPBPH	ht-αLB-400βP6 ISPBPH	ht-αB-356βP6 ISPBPH
2,2′-Dichlorobiphenyl	8.3	0	9	22.5	10.8
3,3′-Dichlorobiphenyl	14.5	0	2.5	0	6.3
2,5-Dichlorobiphenyl	23.3	6.8	21	15.3	21.8
2,2′,5,5′-Tetrachlorobiphenyl	0	1	1	9	0
Biphenyl	34	17	5	Traceb	43

^aBPH dox reactions were carried out as described in Materials and Methods. The reaction was initiated by adding 25 nmol of substrate except for biphenyl (50 nmol). Values refer to amounts of substrate consumed 5 min after initiation of the reaction when 1.2 nmol of enzyme was present except in the case of 2,2′,5,5′-tetrachlorobiphenyl, values for which refer to nanomoles of 3,4-dihydro-3,4-dihydroxy-2,2′,5,5′-tetrachlorobiphenyl produced per 1.2 nmol of enzyme 10 min after initiation of the reaction. 

^bTrace of 2,3-dihydro-2,3-dihydroxybiphenyl detected by HPLC analysis in the reaction medium.