Recombinant proteins are proteins that are artificially produced by combining DNA from different sources. This process typically involves inserting a gene that codes for a specific protein into a host organism, such as bacteria, yeast, or mammalian cells. The host then uses its cellular machinery to produce the desired protein, which can be harvested and purified for various applications. These proteins are essential in many fields, including medicine and research. For example, recombinant proteins are used in the production of insulin for diabetes treatment and in vaccines. They also play a crucial role in studying biological processes and developing new therapies.