Phosphatase and oxygen radical-generating activities of mammalian purple acid phosphatase are functionally independent.
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.
Kaija
Helena
H
Biocenter Oulu, Research Center for Molecular Endocrinology, Oulu University Hospital, University of Oulu, FIN-90014 Finland.
Alatalo
Sari L
SL
Halleen
Jussi M
JM
Lindqvist
Ylva
Y
Schneider
Gunter
G
Väänänen
H Kalervo
HK
Vihko
Pirkko
P
D000135:Acid Phosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D006023:Glycoproteins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013053:Spectrophotometry; D018411:Spodoptera / Q000235:genetics; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D000071681:Tartrate-Resistant Acid Phosphatase
D006023:Glycoproteins; D007527:Isoenzymes; D017382:Reactive Oxygen Species; C091137:purple acid phosphatase; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase