Purification and characterization of peroxidase from date palm cv. Agwa fruits

Figures & data

Table 1. Purification scheme for date palm cv. Agwa peroxidase

Step	Total activity (units*)	Total protein (mg)	S.A. (units/mg protein)	Fold purification	Recovery %
Crude extract	845	18	47	1	100
Chromatography
On DEAE- Sepharose
0.0 M NaCl (POI)	135	1.9	71	1.5	16
0.1 M NaCl (POII)	489	2.19	223	4.75	57
0.2 M NaCl (POIII)	60	1.2	50	1.06	7
0.3 M NaCl (PIV)	55	1.4	39	0.83	6.5
Chromatography on Sephacryl S-200 POII	250	0.4	625	13.2	29.5

*One unit of peroxidase activity is defined as the amount of enzyme which increases the O.D. 1.0 per min under standard assay conditions.

S.A., specific activity.

Figure 1. Chromatography of date palm cv. Agwa on DEAE-Sepharose column. (•___•) Absorbant at 280 nm (x --- x) units/fraction

Figure 2. Chromatography of date palm cv. Agwa POII DEAE-Sepharose fraction on Sephacryl S-200 column. (•___•) Absorbant at 280 nm (x --- x) units/fraction

Figure 3. SDS-PAGE for date palm cv. Agwa POII. 1, molecular markers, 2, sephacryl S-200 POII

Figure 4. pH optimum of date palm cv. Agwa POII. Each point represents the mean of three experiments ± S.E

Figure 5. Temperature optimum of date palm cv. Agwa POII. Each point represents the mean of three experiments ± S.E

Figure 6. Effect of temperature on the thermal stability of date palm cv. Agwa POII. Each point represents the mean of three experiments ± S.E

Table 2. Relative activities of date cv. Agwa POII toward different substrates

Substrate	% Relative activity
Guaiacol	100 ± 3.2
o-Phenylenediamine	76 ± 2.2
o-Dianosidine	58 ± 1.8
p-Aminoantipyrine	35 ± 1.3
Pyrogallol	22 ± 0.07
ABTS	7 ± 0.2

Figure 7. Reciprocal of Lineweaver–Burk plot relating date palm cv. Agwa POII reaction velocities to H₂O_2.

Figure 8. Reciprocal of Lineweaver–Burk plot relating date palm cv. Agwa POII reaction velocities to guaiacol

Table 3. Effect of 5 mM metal cations on date cv. Agwa POII

Metals	% Relative activity
Control	100 ± 4.2
Fe^3+	501 ± 18.3
Cu^2+	303 ± 12.5
Co^2+	198 ± 6.2
Ni^2+	104 ± 3.2
Ca^2+	36 ± 1.2
Zn^2+	27 ± 1.1
Hg^2+	22 ± 0.8