Peptide transport in Candida albicans

The tripeptide L-methionyl-L-methionyl-L-[METHYL-14C]methionine was taken up into Candida albicans by a saturable system with a pH optimum of 3.5, a temperature optimum of 37 degrees C and an apparent Km of 3.3 x 10(-5) M. Metabolic inhibitors such as sodium azide and dinitrophenol completely prevented uptake. Neither methionine nor dimethionine effectively competed with trimethionine uptake. (Leu)3, Gly-Met-Gly, acetyl-(Met)3, D-Met-L-Met-L-Met and Met-Met-Ile effectively competed with (Met)3 uptake, whereas (Lys)3, L-Met-L-Met-D-Met, D-Met-D-Met-D-Met, (Met)3 methyl ester and (Ala)3 did not. Trimethionine was rapidly hydrolysed by a peptidase after entry into the cell.