Review of the comparative biochemistry of pyruvate kinase

Purification of Pyruvate Kinase from Germinating Castor Bean Endosperm

“…5). This value is in the same range as those which have been reported for nonplant PKs (3,13,14,18,23,25). Two bands which stain for protein with equal intensity were observed when the purified castor bean enzyme was subjected to SDS-PAGE (Fig.…”

“…The presence of two bands, which had molecular masses of 57 and 56 kD, respectively, implies that castor endosperm PK is heterotetrameric. In contrast, all PKs purified to date from nonplant sources are homotetramers, with subunit molecular masses ranging from 50 to 70 kD (3,13,14,18,23,25). Despite the use of the protease inhibitors PMSF, leupeptin and chymostatin in the homogenization buffer (as recommended [1]), the possibility exists that the 56 kD castor bean PK subunit is an artifact created by proteolytic cleavage of the 57 kD subunit.…”

“…The enzyme from nonplant sources has been highly purified and studied extensively (3,13,14,18,23,25). All (3,13,14,18,23,25).…”

“…The enzyme from nonplant sources has been highly purified and studied extensively (3,13,14,18,23,25). All (3,13,14,18,23,25). Animal PKs can show very significant regulatory properties with both allosteric mechanisms and reversible protein kinase mediated phosphorylation, used to modulate the activity of the enzyme in vivo (3,13,14,18,23).…”

Relationship between the Subunits of Leucoplast Pyruvate Kinase from Ricinus communis and a Comparison with the Enzyme from Other Sources

“…The (10,14,15,19,24,25). Mammalian PKs are generally homotetrameric with a native Mr of 190,000 to 250,000 (10,19).…”