Table 4.

R. palustris MatB specific activity with a variety of substrates

Enzyme	Substrate	Sp acta	% activity
RpMatB	Malonate	18 ± 2	100
	Methylmalonate	11 ± 1	61
	Ethylmalonate	7 ± 0.5	39
	Butylmalonate	0.8 ± 0.1	4.4
RpMatBK488A	Malonate	0.04 ± 0.01	0.2
	Methylmalonate	0.03 ± 0.01	<0.2

^aSpecific activity is reported as μmol AMP min⁻¹ mg⁻¹. Each compound was tested at a concentration of 2 mM. The specific activity of the enzyme when succinate, propionate, acetate, butyrate, acetoacetate, isobutyrate, isovalerate, β-hydroxybutyrate, or 2-methylsuccinate was used as substrate was <0.03 μmol AMP min⁻¹ mg⁻¹.