A new continuous optical assay for maltase and sucrase.

A new method for the assay of maltase and sucrase is reported. The method makes use of mutarotase, hexokinase and glucose 6-phosphate dehydrogenase as ancillary enzymes. The reaction is linear at least up to a delta E/min of 0.

Neutral maltase of human granulocytes: localization on the extracytoplasmic side of the plasma membrane and some properties.

Neutral maltase is an alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.

A continuous spectrophotometric assay for the enzymatic marker glucose 6-phosphatase.

A continuous spectrophotometric assay for glucose 6-phosphatase is described. The method uses glucose dehydrogenase and mutarotase as ancillary enzymes. Glucose 6-phosphatase activity is measured by following NADH formation at 340 nm.

Isocitrate lyase from Pinus pinea. Characterization of its true substrate and the action of magnesium ions.

We found that the Mg-isocitrate complex is the true substrate for pine isocitrate lyase and that magnesium acts as a non-essential activator. Both the non-activated and the activated enzyme forms are catalytically active. Our model is consistent with the presence of two Mg-binding sites with different affinities: an activator site with high affinity in addition to the catalytic site with lower affinity.