L-Proline is oxidized to pyrroline-5-carboxylic acid in intact plant mitochondria by a proline dehydrogenase (EC 1.4.3) that is bound to the matrix side of the inner mitochondrial membrane (TE Elthon, CR Stewart [1981] Plant Physiol 67: 780-784). This investigation reports the first solubilization of the L-proline dehydrogenase (PDH) from plant mitochondria. The supernatant from NP-40-treated e...

The transport of proline, 5-oxoproline, and pipecolic acid and their mutual interactions during transport were studied in purified brush-border membrane vesicles from rabbit renal cortex. The presence of a Na’ gradient stimulated the transport of these compounds. 5-Oxoproline was transported by a single system with an apparent K,,, of 20.4 mM. Many neutral amino acids and 6-piperidone-2-carboxy...

Scutella separated from germinating grains of barley (Hordeum vulgare L. cv Himalaya) took up 1 millimolar l-[(14)C]proline at an initial rate of about 6.5 micromoles gram(-1) fresh weight hour(-1) (pH 5, 30 degrees C). The uptake had a pH optimum at 5. The bulk of the uptake (93%) was via carrier-mediated active transport. All of the 19 l-amino acids tested at 10 millimolar concentration inhib...

Midlogarithmic phase Leishmania donovani promastigotes accumulate 2-deoxy-D-glucose (2-dGlc) and L-proline, maintaining concentration gradient factors across the surface membrane of 78.7 and 60, respectively. Cyanide (1 mM) and iodoacetate (0.5 mM) inhibited the transport of both substrates. L-proline uptake was also inhibited by 2-dGlc (10 mM). Transport of neither substrate was affected by Na...

Over the past three decades, L-proline has become recognized as an important metabolite for trypanosomatids. It is involved in a number of key processes, including energy metabolism, resistance to oxidative and nutritional stress and osmoregulation. In addition, this amino acid supports critical parasite life cycle processes by acting as an energy source, thus enabling host-cell invasion by the...

hydroponic experiments were performed to exam the dynamic change of endogenous proline in rice seedlings exposed to potassium chromate chromium (vi) or chromium nitrate chromium (iii). although accumulation of both chromium species in rice seedlings was obvious, more chromium was detected in plant tissues of rice seedlings exposed to chromium (iii) than those in chromium (vi), majority being in...

Several chronic lung diseases have been linked to cigarette smoking (Chronic Obstructive Pulmonary Disease (COPD), and cancer are associated with increased tobacco use). We recently described a collagen fragment, proline-glycine-proline (PGP), chemotactic for neutrophils, that appears to play a role in COPD, cystic fibrosis, and bronchiolitis obliterans syndrome. PGP can exist in either its n...

The complete Bacillus subtilis genome contains four genes (proG, proH, proI, and comER) with the potential to encode Delta(1)-pyrroline-5-carboxylate reductase, a proline biosynthetic enzyme. Simultaneous defects in three of these genes (proG, proH, and proI) were required to confer proline auxotrophy, indicating that the products of these genes are mostly interchangeable with respect to the la...

In unfolded RNase A there is an interconversion between slow-folding and fast-folding forms (U(S) right harpoon over left harpoon U(F)) that is known to show properties characteristic of proline isomerization in model peptides. Here, we accept the evidence that U(S) molecules contain nonnative proline isomers and we ask about the isomerization of these proline residues during folding. The U(S) ...