Peroxidase Activity in Aloe barbadensis Commercial Gel: Probable Role in Skin Protection

A basic peroxidase (EC 1.11.1.7) (pI around 9.0) has been identified in commercial gel of Aloe barbadensis. In vivo , the activity is localised in the vascular system of inner aqueous leaf parenchyma. Some relevant properties of this basic peroxidase of Aloe have been investigated in leaf extract and in commercial gel where it is notably stable. The acid optimum pH (5.0) for activity and the low K M for H 2 O 2 (0.14 mM) suggest that, when topically applied, Aloe peroxidase may scavenge H 2 O 2 in skin surface. Abbreviations 4-MN:4-methoxy-α-naphthol BSA:bovine serum albumin EGTA:ethylene glycol-bis(β-aminoethyl ether) N,N,N′, N′ -tetraacetic acid HQ: p -hydroquinone IEF:isoelectrofocusing IALP:inner aqueous leaf parenchyma PVDF:polyvinylidene difluoride ROS:reactive oxygen species pI:isoelectric pH