. Author manuscript; available in PMC: 2017 Oct 18.

Published in final edited form as: J Toxicol Environ Health A. 2009;72(9):577–584. doi: 10.1080/15287390802706371

TABLE 1.

Kinetic Parameters of Human Lens ALDH1A1 Using Various Substrates

Substrate	V_max (nmol/min/mg)	K_m (µM)	V_max/K_m^b
Acetaldehyde	631.4 ± 10.9	238.2 ± 12.9	2.7
Benzaldehyde	750.3 ± 121.3	143.2 ± 6.4	5.2
HNE	135 ± 15.2^a	4.8 ± 0.12^a	28.1^a
Propionaldehyde	445.3 ± 34.4	121.4 ± 6.7	3.7
Malonaldehyde	381.6 ± 11.4	3.5 ± 0.6	109.0
trans-2-Heptenal	155.8 ± 7.3	177.1 ± 11.7	0.88
NAD	149.7 ± 4.9	59.4 ± 2.4	2.5

Note. Enzyme activities were measured in a mixture of 100 mM sodium pyrophosphate (pH 8.0) with 50 µg purified ALDH1A1, 1 mM dTT, 2 mM NAD⁺, and various concentration of substrates (10 µM to 3200 µM) by spectrophotometer at 340 nm for 5 min. For NAD⁺, 1 mM propionaldehyde was used as the substrate. K_m and V_max for various ALDH1A1 substrates and NAD⁺ were calculated using Sigma and Prizm software. Values are represented as mean ± SD.

Parameters were determined at pH 7.0.

V_max/K_m represents the catalytic efficiency of ALDH1A1.