Catalytic Properties and the Role of Copper in Bovine and Lentil Seedling Copper/Quinone-Containing Amine Oxidases: Controversial Opinions

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

Download Full-text

Phosphofructokinase from bumblebee flight muscle. Molecular and catalytic properties and role of the enzyme in regulation of the fructose 6-phosphate/fructose 1,6-bisphosphate cycle.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)77867-3 ◽

1988 ◽

Vol 263 (33) ◽

pp. 17527-17533

Author(s):

A Leite ◽

J A Neto ◽

J F Leyton ◽

O Crivellaro ◽

H A el-Dorry

Keyword(s):

Flight Muscle ◽

Catalytic Properties ◽

Fructose 1,6 Bisphosphate

Download Full-text

ChemInform Abstract: The Reductive and Oxidative Half-Reactions and the Role of Copper Ions in Plant and Mammalian Copper-Amine Oxidases.

ChemInform ◽

10.1002/chin.200111286 ◽

2001 ◽

Vol 32 (11) ◽

pp. no-no

Author(s):

Alessandra Padiglia ◽

Rosaria Medda ◽

Andrea Bellelli ◽

Enzo Agostinelli ◽

Laura Morpurgo ◽

...

Keyword(s):

Copper Ions ◽

Amine Oxidases ◽

Copper Amine Oxidases ◽

Copper Amine

Download Full-text

Role of Active-Site Residues 107 and 108 of GlutathioneS-Transferase mGSTA4-4 in Determining the Catalytic Properties of the Enzyme for 4-Hydroxynonenal

Archives of Biochemistry and Biophysics ◽

10.1006/abbi.1998.1009 ◽

1999 ◽

Vol 362 (1) ◽

pp. 167-174 ◽

Cited By ~ 5

Author(s):

Bindu Nanduri ◽

Piotr Zimniak

Keyword(s):

Active Site ◽

Catalytic Properties ◽

Active Site Residues

Download Full-text

Enhancement of aromatase activity by D-aspartic acid in the ovary of the lizard Podarcis s. sicula

Reproduction ◽

10.1530/rep.0.1210803 ◽

2001 ◽

pp. 803-808 ◽

Cited By ~ 36

Author(s):

L Assisi ◽

V Botte ◽

A D'Aniello ◽

MM Di Fiore

Keyword(s):

Amino Acids ◽

Aspartic Acid ◽

Reproductive Cycle ◽

Catalytic Properties ◽

Ovarian Tissue ◽

Experimental Treatment ◽

Tissue Homogenate ◽

Aromatase Activity

The present study investigated the role of D-aspartic acid (D-Asp) in ovarian steroidogenesis and its effect on aromatase activity in the lizard, Podarcis s. sicula. It was determined that D-Asp concentrations vary significantly during phases of the reproductive cycle: they vary inversely with testosterone concentrations and directly with oestradiol concentrations in the ovary and plasma. Experimental treatment showed that administration of D-Asp induces a decrease in testosterone and an increase in oestradiol, and that treatment with other amino acids (L-Asp, D-Glu and D-Ala) instead of D-Asp has no effects. Experiments in vitro confirmed these results. Furthermore, these experiments showed an increase in aromatase activity, as the addition of D-Asp either to fresh ovarian tissue homogenate or to acetonic powder of ovarian follicles induced a significant increase in the conversion of testosterone to oestradiol. Aromatase activity is four times greater in the presence of D-Asp than in its absence. However, almost equivalent values of the two K(m) values (both approximately 25 nmol l(-1)) indicate that aromatase has the same catalytic properties in both cases.

Download Full-text