A survey of 56 normal and neoplastic tissues has shown that plasminogen activators were released by cultured human cells in several molecular weights and their susceptibility to inhibition by antibodies to the normal urinary enzyme, urokinase. Melanoma cells characteristically secreted plasminogen activators which were immunochemically distinct from urokinase and which migrated on sodium dodecy...

Glycogen synthetase D was inactivated by treatment with trlnitrobenzene sulfonate with the incorporation of 2.5 moles of trinitrophenyl group per mole of enzyme subunit. ‘I he sulfhydryl content of the enzyme was unchanged during trinitrophenylation indicating that derivatization was through the amino group. Glucose-6-P and other phosphate activators of glycogen synthetase D offered protection ...

Guanine, queuine-tRNA transglycosylase has been purified from wheat germ to homogeneity. The specific activity is 2,000 pmol h-1 mg-1 of protein. The enzyme has an apparent Mr = 140,000. It migrates as a single band with Mr = 68,000 on electrophoresis in sodium dodecyl sulfate gels, indicating two Mr = 68,000 subunits. Both guanine (Km = 6.0 X 10(-8) M) and queuine (KI = 9.5 X 10(-8) M) are sub...

ADP-glucose (Glc) pyrophosphorylase (AGPase), a key regulatory enzyme in starch biosynthesis, is highly regulated. Transgenic approaches in four plant species showed that alterations in either thermal stability or allosteric modulation increase starch synthesis. Here, we show that the classic regulators 3-phosphoglyceric acid (3-PGA) and inorganic phosphate (Pi) stabilize maize (Zea mays) endos...

Permeabilized germlings from the dimorphic fungus Mucor rouxii were used for in situ measurement of protein kinase A (PKA) activation, to compare the results with those obtained in vitro at low or high (nonlinear) enzyme concentrations. The apparent total activity per cell when measured in situ is 5- to 10-fold lower than the in vitro measured activity in crude extracts from those cells. Polyam...

Piasminogen activators (PA) l are thought to play a role in the proteolytic events associated with cell migration and tissue destruction and remodeling (1), in particular in the context of inflammation (2). Indeed, monocytes and macrophages from both human and murine origin produce PA (3, 4), and the secretion of these enzymes has been linked with the participation of mononu¢lear phagocytes in ...

Many phase I and II microsomal enzyme inducers share common mechanisms of transcriptional activation and thus share a similar battery of genes that are coordinately regulated. Many phase II metabolites are thought to be transported out of cells by multidrug resistance proteins 1, 2, and 3 (Mrp1, 2, and 3). The purpose of this study was to determine the organ distribution of these three transpor...

1. Proteins, when added to activators (sodium oleate. Aerosol) of protyrosinase, greatly decrease the degree of activation. 2. Certain proteins adsorbed on activator micelles are markedly affected by temperature and are rendered more sensitive by ultraviolet light. 3. Ideas are expressed as to the possible nature of activating and inhibiting phenomena especially as they relate to the enzyme tyr...