The Mononuclear Molybdenum Enzymes

Molybdenum enzymes.

There are many molybdenum-containing enzymes distributed throughout the biosphere. The availability of molybdenum to biological systems is due to the high water solubility of oxidized forms of the metal. Molybdenum enzymes can be grouped on the basis of the structure of the metal centre. Three principal families of enzyme exist, with active sites consisting of (ppt)MoOS(OH) (the molybdenum hydr...

Mechanistic aspects of molybdenum-containing enzymes.

Molybdenum-cofactor-containing enzymes: structure and mechanism.

Molybdenum-containing enzymes catalyze basic metabolic reactions in the nitrogen, sulfur, and carbon cycles. With the exception of the nitrogenase cofactor, molybdenum is incorporated into proteins as the molybdenum cofactor that contains a mononuclear molybdenum atom coordinated to the sulfur atoms of a pterin derivative named molybdopterin. Certain microorganisms can also utilize tungsten in ...

Pyranopterin conformation defines the function of molybdenum and tungsten enzymes.

We have analyzed the conformations of 319 pyranopterins in 102 protein structures of mononuclear molybdenum and tungsten enzymes. These span a continuum between geometries anticipated for quinonoid dihydro, tetrahydro, and dihydro oxidation states. We demonstrate that pyranopterin conformation is correlated with the protein folds defining the three major mononuclear molybdenum and tungsten enzy...

Hydrolytic Enzymes of Rabbit Mononuclear Exudate Cells

Oil-induced mononuclear phagocytes (MN) were quantitatively assayed for various hydrolases as unfractionated suspensions of frozen and thawed cells. They apparently contain two proteases. The first, measured with urea- or acid-denatured hemoglobin, was similar to purified Proteinase I of lung with respect to pH optimum (pH 4), stability, hydrolytic and polymerizing activities, and reactions to ...