TonB-dependent transporters (TBDTs) are bacterial outer membrane proteins that allow active high affinity transport of large substrate molecules, among which iron-siderophore complexes, vitamin B12, and various carbohydrates [ 92- 95].
The second observation is the lower degree of conservation of chaperonin substrates among organisms, which suggests that chaperonin substrates emerged later on in evolutionary history.
The lignin synthesis pathway involves many substrates and enzymes, among which the CAD enzyme catalyzes the last step in the synthesis of monolignol precursors.
In addition to APP, γ-secretase cleaves more than 50 other substrates [18] in a similar manner, among which the Notch receptor is the most characterized.
Finally, 1547 confidential human TSPs are identified for further manual curation, among which 58.37% pairs with novel substrates not annotated in public transporter databases.
The degradation timing of substrates is thus determined collectively by substrate-APC/CCdc20 interactions and APC/CCdc20 partitioning among substrates, both of which are influenced by differences in kinetic parameters among substrates.
The function of proteases is regulated either by controlling the spatial and temporal activity or through their ability to discriminate among potential substrates, of which the last is probably the most important mechanism.
The impact of competition depends on how APC/CCdc20 is partitioned among its substrates, which is determined by the relative concentrations of APC/CCdc20 and all of its substrates, and the relative strengths of substrate-specific kinetic parameters.
DA-CS hydrolysate showed the highest percentage xylose consumption among the three substrates (91%), which relates to low initial concentration of xylose (4 g/L) in DA-CS hydrolysate, whereas AFEX-CS and IL-CS hydrolysates contained 29 g/L and 35 g/L of xylose, respectively.
