Perturbation of folding and reassociation of lactate dehydrogenase by proline and trimethylamine oxide.

Investigations of protein-solute interactions typically show that osmolytes favor native conformations. In this study, the effects of representative compatible and counteracting osmolytes on the reactivation of lactate dehydrogenase from two different conformational states were explored. Contrary to expectations, proline and trimethylamine oxide inhibited both the initial time course and the extent of reactivation of lactate dehydrogenase from bovine heart following denaturation in guanidine hydrochloride, as well as following inactivation at pH 2.

AMP-deaminases from chicken and rabbit muscle: partial primary sequences of homologous 17-kDa CNBr fragments: autorecognition by rabbit anti-[chicken AMPD].

The apparent size (87.5 kDa) of the major polypeptide in freshly isolated chicken muscle AMP deaminase (AMPD.M) was comparable with that predicted from the sequences of the genes for the major muscle isoforms from human and rat.

Contrast in adenine uptake by chicken and rabbit erythrocytes in vitro.

1. Relative to rabbit erythrocytes, chicken red blood cells exhibit a much greater capacity to utilize [3H]adenine for nucleotide synthesis in vitro, even at 5 degrees C and in the absence of added inorganic phosphate. 2.

Pyrroline-5-Carboxylate Reductase in Soybean Nodules : Comparison of the Enzymes in Host Cytosol, Bradyrhizobium japonicum Bacteroids, and Cultures.

Characteristics of pyrroline-5-carboxylate reductase (P5CR) from Bradyrhizobium japonicum bacteroids and cultured rhizobia were compared with those of the enzyme in soybean nodule host cytosol. Reductase from host cytosol differed from that in bacteroids in: (a) the effect of pH on enzymic activity, (b) the capacity to catalyze both reduction of pyrroline-5-carboxylic acid and NAD(+)-dependent proline oxidation, (c) apparent affinities for pyrroline-5-carboxylic acid, and (d) sensitivities to inhibition by NADP(+) and proline. The K(1) for proline inhibition of P5CR in bacteroid cytosol was 1.

Pyrroline-5-carboxylate reductase in soybean nodules: isolation/partial primary structure/evidence for isozymes.

Electrophoretic evidence was obtained for two forms of pyrroline-5-carboxylate reductase (P5CR) in soybean nodules. One form was purified over 2300-fold. The apparent sizes of the polypeptides comprising the pyrroline-5-carboxylate reductases from soybean cytosol (29,700) and Escherichia coli (28,000) were consistent with those predicted from the sequences of the genes encoding them (Deutch et al.