[Development for the determination of band 5b tartrate-resistant acid phosphatase activity in serum]

Band 5 Tartrate-resistant acid phosphatase(TRACP; EC 3.1.3.2) consists of two isoenzymes, bands 5a and 5b, of which band 5b TRACP, an enzyme expressed in bone-resorbing osteoclasts, is secreted into the circulation during bone resorption. Band 5b TRACP was measured kinetically in serum as tartrate-resistant fluoride-sensitive heparin-resistant ACP with 2,6-dichloro-4-acetylphenyl phosphate as substrate at pH6.6. The within-run(n = 20) and between-run(n = 20) CVs of band 5b TRACP activity were 3.3-5.8% and 5.0-7.3%, respectively. The reference range of band 5b TRACP activity in males(n = 72) and females(n = 87) 20-39 years of age by this method were 3.7-12.5 U/l and 2.7-9.9 U/l, respectively. The band 5b TRACP value was significantly higher in post-menopausal women compared with the menstruating women. The relationship of band 5b TRACP and ultrasound findings in healthy women aged 31-75 years(n = 139) were inversely correlated with stiffness(r = -0.401), speed of sound(SOS; r = -0.386) and broadband ultrasound attenuation(BUA; r = -0.338). These results suggest that band 5b TRACP may be a useful in the evaluation of bone turnover.