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. Author manuscript; available in PMC: 2020 Apr 29.
Published in final edited form as: Hum Mutat. 2019 Jun 18;40(10):1731–1748. doi: 10.1002/humu.23777

Table 3 |.

Kinetic Parameters of the novel missense mutations in the ELAC2 endonuclease with the pre-mt-tRNALeu(UUR) substrate

Mutant # Trials Mut. /
WT		 kcat
(min−1)		 KM
(nM)		 kcat/KM
(x 108 M−1min−1)		 Relative
kcat 		Relative
KM 		Relative
kcat/KM *
WT 34 20.2±2.1 43±7.7 6.2±0.56
Arg68Trp 4 4.7 1.9±0.36 37±16 0.81±0.22 0.13±0.032 0.79±0.25 0.20±0.038
Gln388Arg 4 1.9 1.2±0.46 14±7.8 1.5±0.66 0.075±0.023 0.43±0.18 0.38±0.17
Leu422Val 3 0.94 9.1 ±3.5 30±15 4.0±1.5 0.59±0.081 1.6±0.39 0.39±0.060
Pro493Leu 4 55 0.09±0.02 99±51 0.014±0.0035 0.006±0.002 2.0±0.8 0.005±0.002
Arg564Ser 4 1.1 44.1±19.3 40±27 11±2.8 2.2±0.68 2.5±1.3 1.1±0.16
Lys660Ile 5 1.8 3.2±1.4 25±10 1.5±0.23 0.23±0.12 1.2±0.54 0.32±0.10
Ala680Val 4 2.2 4.8±1.6 14±4.8 4.0±1.2 0.23±0.05 0.59±0.22 0.62±0.24
Tyr729Cys 3 82 0.1±0.01 23±8.2 0.056±0.022 0.006±0.001 0.77±0.26 0.0075±0.0015
His749Tyr 6 5.5 1.1±0.12 23±8.2 1.1±0.23 0.06±0.01 0.45±0.15 0.18±0.044
Arg781His 3 6.9 7.6±0.70 131±24 0.63±0.14 0.37±0.17 2.9±1.1 0.12±0.013

Column designation, from left: (column 1) Variant: wild-type (WT) or mutant ELAC2. (column 2) Number of times variant processing experiments were performed. (column 3) The ratio of mutant to WT concentration depending on the impairment factor. (columns 4–6) kcat, KM, kcat/KM: values reported are means of replicate experiments. Values following ± are standard errors. (columns 7–9) kcat, KM and kcat/KM relative to WT (e.g. the quotient [kcat mutant]/[kcat WT]).

*

Reported variant relative to WT values are the means and standard errors for specific experiments performed on the same day, rather than the compiled values at the top of the table, therefore differ from results that would be obtained by comparing values in columns to the left with aggregate means for WT (first row). Regular font – no impairment of enzymatic activity (> 0.8 of WT) or not statistically significant. Italic – mild impairment of enzymatic activity (0.8 – 0.2 of WT). Bold – severe impairment of enzymatic activity (< 0.2 of WT).