Hello Kushal Junghare

TPCK irreversibly inhibits the serine protease α-chymotrypsin. TPCK has been shown to specifically alkylate the histidine-57 moiety in the active center of chymotrypsin and chymotrypsin-like serine proteases.

Thus, TPCK is designed to react specifically with the active center of chymotrypsin, completely inhibiting the proteolytic activity of chymotrypsin with little effect on the activity of trypsin.

The use of TPCK is necessary during IAV infection because it will help to impair the activity of contaminating chymotrypsin, which does not promote IAV infectivity but can cause damage to cell monolayers.

Therefore, it is usually recommended to use TPCK-treated trypsin for IAV cultures in cell lines.

Best.