Multiple molecular forms of avian aldolases. II. Enzymic properties and amino acid composition of chicken (Gattus domesticus) breast muscle aldolase

Abstract

Several properties of crystalline chicken (Gallus domesticus) breast muscle aldolase (fructose 1,6-diphosphate–D-glyceraldehyde 3-phosphate lyase, EC 4.1.2.13) were determined. The enzyme was found to have a broad pH optimum centered around pH 7.1 and to be remarkably stable over a wide pH range. The temperature coefficient Q10 is 2.6 in the range from 10 to 35 °C. The enzyme is stable at 48 °C for 10 min and almost completely inactivated at 55 °C. The apparent Michaelis constants for fructose 1,6-diphosphate and fructose 1-phosphate were 4.2 × 10−5 M and 1.7 × 10−2 M, respectively. The phosphate inhibitor constant (K1) was 5.5 × 10−3 M.Chicken breast muscle aldolase is similar to the rabbit enzyme in many of the above properties, although there are significant differences in heat stability and amino acid composition.