(1) Studies on a novel magnesium-dependent, calcium-inhibited protein phosphatase revealed that it can be activated by its protein activator about 360-fold with an activation constant of 0. 1 micromolar. The enzyme contains a single methionine and half of the amino acid residues are either acidic or basic. The possibility that the enzyme may be a tyrosine phosphatase has been ruled out. (2) Site-directed mutagenesis of Escherichia coli ribonucleotide reductase revealed that the carboxyl terminus of the B2 subunit is the key region involved in Bl-B2 subunit interaction and possibly electron transfer during catalysis. (3) Kinetic methods for differentiation of (a) simultaneous binding of two inhibitor molecules in linear or nonlinear competitive inhibition and (b) whether a low enzymatic activity association with a mutant enzyme is due to wild type contamination or residual intrinsic activity, have been developed.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Intramural Research (Z01)
Project #
1Z01HL000224-14
Application #
3857958
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
14
Fiscal Year
1991
Total Cost
Indirect Cost
Name
National Heart, Lung, and Blood Institute
Department
Type
DUNS #
City
State
Country
United States
Zip Code