If you write Chinese directly, you don't need italics. If you write English with the first capital in italics, the following letters will do.

Enzymes in the human body include digestive enzymes, transaminase, DNA transcriptase, RNA transcriptase and other enzymes. Enzymes in the human body have different functions. If you lack an enzyme in your body, then the whole person will be finished, and all the systems of the whole person will collapse.