Kaija Helena, Alatalo Sari L, Halleen Jussi M, Lindqvist Ylva, Schneider Gunter, Väänänen H Kalervo, Vihko Pirkko
Biocenter Oulu, Research Center for Molecular Endocrinology, Oulu University Hospital, University of Oulu, FIN-90014 Finland.
Biochem Biophys Res Commun. 2002 Mar 22;292(1):128-32. 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.
骨吸收破骨细胞和活化巨噬细胞表达大量抗酒石酸酸性磷酸酶（TRAP），这是一种含铁酶，其生物学功能未知。我们研究了重组大鼠TRAP的酸性磷酸酶（AcP）和活性氧（ROS）生成活性。AcP活性的最适pH为4.5，ROS生成活性的最适pH为6.5。通过定点诱变将His113和His216替换后，AcP活性受到严重抑制，但对ROS生成活性没有显著影响。突变不影响底物特异性。这些结果表明，TRAP的AcP和ROS生成活性在功能上是独立的。
