Improvement of the activity and thermostability of microbial transglutaminase by multiple-site mutagenesis

Figures & data

Table 1. Biochemical properties of wild-type MTG and its variants.

Name	Mutation	Spec. activity (U/mg)	t1/2 (50 °C) (min)	Relative increase in t1/2 (50 °C)	t1/2 (60 °C) (min)	Relative increase in t1/2 (60 °C)
WT	None	25.4 ± 0.5^a	40.1	1	2.5	1
DM01	S2P-S23V-Y24N-S199A-K294L	55.7 ± 1.4^b	418.2	10.4	24.8	9.9
DM02	S2P-S23V-Y24N-K269D-K294L	53.2 ± 0.9^b	357.1	8.9	14.4	5.8
DM03	S23V-Y24N-K269D-H289Y-K294L	44.9 ± 0.8^c	377.2	9.4	16.1	6.4

Data of specific activity are presented as mean ± SD of triplicate observations. Values with different superscripts are significantly different (p < 0.05).

Figure 1. Schematic illustration of three penta-site MTG mutations. The mutated amino acids are colored in red and the catalytic triad is colored in blue. (A): DM01; (B): DM02; (C): DM03.

Figure 2. Thermostability tests of MTG and its three penta-site mutations. Error bar presents standard deviation. (A): Specific activity at various temperatures; (B): thermostability of selected thermostable variants at 60 °C; (C): thermostability of selected thermostable variants at 50 °C.