Phosphatase and Oxygen Radical-Generating Activities of Mammalian Purple Acid Phosphatase Are Functionally Independent

• Published in: Biochemical and biophysical research communications Vol. 292; no. 1; pp. 128 - 132
• Main Authors: Kaija, Helena, Alatalo, Sari L., Halleen, Jussi M., Lindqvist, Ylva, Schneider, Gunter, Kalervo Väänänen, H., Vihko, Pirkko
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 22.03.2002
• Subjects: Acid Phosphatase - chemistry; Acid Phosphatase - genetics; Acid Phosphatase - metabolism; AcP; Animals; Binding Sites; Cell Line; Glycoproteins - metabolism; Hydrogen-Ion Concentration; Isoenzymes - chemistry; Isoenzymes - genetics; Isoenzymes - metabolism; Kinetics; Medicin och hälsovetenskap; Models, Molecular; Mutagenesis, Site-Directed; purple acid phosphatase; Rats; Reactive Oxygen Species - metabolism; ROS; site-directed mutagenesis; Spectrophotometry; Spodoptera - genetics; Structure-Activity Relationship; Substrate Specificity; Tartrate-Resistant Acid Phosphatase; site-directed mutagenesis; purple acid phosphatase; ROS; substrate specificity; AcP
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.2002.6615

Bone-resorbing osteoclasts and activated macrophages express large amounts of tartrate-resistant acid phosphatase (TRAP), an iron-containing enzyme with unknown biological function. We studied acid phosphatase (AcP) and reactive oxygen species (ROS)-generating activities of recombinant rat TRAP. pH optimum was 4.5 for AcP activity and 6.5 for ROS-generating activity. Replacement of His113 and His216 by site-directed mutagenesis severely inhibited AcP activity, but had no significant effects on ROS-generating activity. Substrate specificity was not affected by the mutations. These results suggest that AcP and ROS-generating activities of TRAP are functionally independent.