Details

Autor(en) / Beteiligte

• Davidi, Dan
• Noor, Elad
• Liebermeister, Wolfram
• Bar-Even, Arren
• Flamholz, Avi
• Tummler, Katja
• Barenholz, Uri
• Goldenfeld, Miki
• Shlomi, Tomer
• Milo, Ron

Titel

Global characterization of in vivo enzyme catalytic rates and their correspondence to in vitro k cat measurements

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2016-03, Vol.113 (12), p.3401-3406

Ort / Verlag

National Academy of Sciences

Erscheinungsjahr

2016

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Turnover numbers, also known as k cat values, are fundamental properties of enzymes. However, k cat data are scarce and measured in vitro, thus may not faithfully represent the in vivo situation. A basic question that awaits elucidation is: how representative are k cat values for the maximal catalytic rates of enzymes in vivo? Here, we harness omics data to calculate k max vivo , the observed maximal catalytic rate of an enzyme inside cells. Comparison with k cat values from Escherichia coli, yields a correlation of r² = 0.62 in log scale (p < 10−10), with a root mean square difference of 0.54 (3.5-fold in linear scale), indicating that in vivo and in vitro maximal rates generally concur. By accounting for the degree of saturation of enzymes and the backward flux dictated by thermodynamics, we further refine the correspondence between k max vivo and k cat values. The approach we present here characterizes the quantitative relationship between enzymatic catalysis in vitro and in vivo and offers a high-throughput method for extracting enzyme kinetic constants from omics data.