Key active sites of proteases and protease inhibitors: a review / 生物工程学报

Proteases are widely found in organisms participating in the decomposition of proteins to maintain the organisms' normal life activities. Protease inhibitors regulate the activities of target proteases by binding to their active sites, thereby affecting protein metabolism. The key amino acid mutations in proteases and protease inhibitors can affect their physiological functions, stability, catalytic activity, and inhibition specificity. More active, stable, specific, environmentally friendly and cheap proteases and protease inhibitors might be obtained by excavating various natural mutants of proteases and protease inhibitors, analyzing their key active sites by using protein engineering methods. Here, we review the studies on proteases' key active sites and protease inhibitors to deepen the understanding of the active mechanism of proteases and their inhibitors.

Nonoperative management of ankle arthritis

Although hip and knee osteoarthritis are mostly of primary origin, ankle osteoarthritis is of posttraumatic origin. In sports injuries, the ankle is the second most commonly injured body site after the knee. In addition, compared to the cartilage in the knee joint, ankle cartilage has a higher content of proteoglycans and water, and an increased rate of proteoglycan turnover and synthesis, all of which are responsible for its increased incidence of posttraumatic origin osteoarthritis. Nonoperative management of ankle arthritis typically starts with weight reduction, activity modification, and oral non-steroidal anti-inflammatory drugs, physical therapy, and can progress to gait-aids including a cane, shoe-wear modification, patellar tendon weight-bearing ankle-foot orthosis, and intra-articular injections with corticosteroids or hyaluronic acid.