The papain-like protease (PLPro) is a highly conserved, non-structural protein that plays a crucial role in the formation of the replication-transcription complex and the processing of polyproteins in SARS-CoV-2, as well as improving the host’s antiviral immune responses against said virus. Chalcone is a common ingredient, which can be found in a multitude of natural substances, such as food and herbs. It has been proven to have various biological activities, including antiviral effects. Previous studies have identified several natural chalcone-based compounds with the ability to inhibit SARS-CoV-2 by targeting the PLPro enzyme. Based on these findings, this study investigated potential chalcone-derived PLPro inhibitors, as retrieved from Pubchem and in-house libraries. Virtual screening protocols, specifically molecular docking and molecular dynamics simulating filter, were applied to reach the desired goal. As a result, 1448 out of 1454 chalcone derivatives can effectively bind to SARS-CoV-2 via PLPro. The 5 substances with the most suitable docking score and binding mode were selected for the next step. Through MD, CID1021201513 and CID101585417 showed the greatest potential in targeting PLPro. However, further in vitro and in vivo studies must be conducted before the bio-activities of these chalcones against SARS-CoV-2 can be confirmed. Furthermore, the ligand-protein interaction mode analysed in this research can help design effective chalcone derivatives.

Enzymes are biodegradable catalysts naturally present in living organisms. Enzymes can accelerate biochemical reactions by reducing the activation energy, and they are not consumed during reaction processes. Numerous applications of enzymes have been developed in biotechnology, industry, medicine, pharmaceuticals, food processing, biofuels, and so on. In this study, we develop a mathematical model describing enzymatic reactions with a Ping-Pong mechanism and competitive substrate inhibition. In order to obtain insights into the model behaviors, we use Python software to obtain numerical solutions for the model. Some discussions on the numerical results is provided. Finally, we briefly discuss a potential application of the model and some future work.

Enzyme pectinase được ứng dụng trong nhiều lãnh vực sản xuất khác nhau. Việc tận dụng thành phần pectin có trong trái cà phê để cảm ứng sinh pectinase không chỉ giúp tận dụng tốt nguồn phế liệu này mà còn giúp nâng cao hiệu quả quá trình chế biến cà phê theo phương pháp ướt. Trên môi trường bán rắn, hiệu quả sinh tổng hợp pectinase của chủng Aspergillus niger Đ3 không cao, hoạt độ tối ưu chỉ đạt 0,88 UI/g trên môi trường có chứa 20% vỏ cà phê sau 5 ngày nuôi cấy. Ngược lại, thành phần pectin trong lớp nhớt của trái cà phê có khả năng cảm ứng Bacillus Ba 79 sinh pectinase với hiệu quả khá cao, hoạt độ enzyme tối đa đạt 2,33 UI/g sau 4 ngày nuôi cấy trên môi trường có chứa 60% dịch nhớt cà phê, 16% bắp xay và 24% bã đậu nành. Chế phẩm pectinase từ Bacillus Ba 79 có khả năng làm tăng độ trong của rượu vang 41,8% khi bổ sung với tỷ lệ 7,5 UI/ lít, trong thời gian 180 phút.