Table I.

Synthesis of H₂O₂ by peroxidase plus Cys

Sample	H2O2 Synthesis	Guaiacol Peroxidase Activity
	relative units	mm min−1
Horseradish peroxidase	100	20  ± 4
Rose filtrate	0.4	6.3  ± 0.4
Rose eluate	−0.05	3.0  ± 0.1
Horseradish peroxidase followed by rose filtrate	8.3
Horseradish peroxidase followed by rose eluate	12.5

A mixture containing 50 mm sodium borate, pH 8.5, 2 μg mL⁻¹ luminol, and 5 μm Cys was placed in a scintillation counter and counted on single-channel mode for 1 min, during which time luminescence decayed to a low level. Volumes of samples containing peroxidase activity (commercial horseradish peroxidase, filtrate from a 9-d-old rose cell culture, or 1 m KCl eluate from the filtered rose cells) were then added and the mixtures were recounted. Values show the increase in chemiluminescence relative to that seen with horseradish peroxidase (alone). Guaiacol peroxidase activities of the same volumes of each sample were measured spectrophometrically at 470 nm in 50 mm phosphate buffer, pH 6.1, in 16 mm guaiacol, and in 2 mm H₂O₂.