The study by Wang et al. (1989) describes the purification and characterization of recombinant human bone morphogenetic protein (BMP) 2A produced in Chinese hamster ovary (CHO) cells. The researchers found that a single dose of BMP-2A could induce bone formation in rats, with the time and extent of bone formation depending on the amount of BMP-2A implanted. A dose-response and time-course study using the rat ectopic bone formation assay revealed that implantation of 0.5–115 μg of partially purified recombinant human BMP-2A resulted in cartilage by day 7 and bone formation by day 14. The activity of the recombinant BMP-2A was histologically indistinguishable from that of bone extracts, suggesting its therapeutic potential for promoting de novo bone formation in humans. The study also highlights the importance of BMP-2A in bone formation and its potential as a therapeutic agent for bone-related conditions.The study by Wang et al. (1989) describes the purification and characterization of recombinant human bone morphogenetic protein (BMP) 2A produced in Chinese hamster ovary (CHO) cells. The researchers found that a single dose of BMP-2A could induce bone formation in rats, with the time and extent of bone formation depending on the amount of BMP-2A implanted. A dose-response and time-course study using the rat ectopic bone formation assay revealed that implantation of 0.5–115 μg of partially purified recombinant human BMP-2A resulted in cartilage by day 7 and bone formation by day 14. The activity of the recombinant BMP-2A was histologically indistinguishable from that of bone extracts, suggesting its therapeutic potential for promoting de novo bone formation in humans. The study also highlights the importance of BMP-2A in bone formation and its potential as a therapeutic agent for bone-related conditions.