| The ejaculate composition is extremely complicated and variable among livestock species. The seminal proteins and enzymes are vital for ejaculate metabolism, spermatozoa performance, survival, and transport within the feminine reproductive tract. Proteases and proteinase inhibitors are secreted by the accessory sex glands of the male reproductive tract and find mixed with the spermatozoa throughout ejaculation. But an entire understanding of those enzymes and their performance in numerous class species is not obtainable. The performance of the assorted proteinases and protease inhibitors of ejaculate stay a mystery, and only a few studies are conducted concerning the characterization of those enzymes. Throughout this review, we tend to target the current understanding of the key proteases and their inhibitors of ejaculate from various mammalian species.