scholarly journals Purification and Characterization of Hydroxypyruvate Reductase from Cucumber Cotyledons

1983 ◽  
Vol 72 (2) ◽  
pp. 402-408 ◽  
Author(s):  
David E. Titus ◽  
David Hondred ◽  
Wayne M. Becker
Keyword(s):  
Purification And Characterization ◽  
Hydroxypyruvate Reductase ◽  
Cucumber Cotyledons

scholarly journals Purification and characterization of a novel NADPH(NADH)-dependent glyoxylate reductase from spinach leaves. Comparison of immunological properties of leaf glyoxylate reductase and hydroxypyruvate reductase

1986 ◽  
Vol 239 (3) ◽  
pp. 653-659 ◽  
Author(s):  
L A Kleczkowski ◽  
D D Randall ◽  
D G Blevins
Keyword(s):  
High Specificity ◽  
Maximal Activity ◽  
Purification And Characterization ◽  
Leaf Extracts ◽  
Hydroxypyruvate Reductase ◽  
Ph Range ◽  
Glyoxylate Reductase ◽  
Spinach Leaves

A novel reductase displaying high specificity for glyoxylate and NADPH was purified 3343-fold from spinach leaves. The enzyme was found to be an oligomer of about 125 kDa, composed of four equal subunits of 33 kDa each. A Km for glyoxylate was about 14-fold lower with NADPH than with NADH (0.085 and 1.10 mM respectively), but the maximal activity, 210 mumol/min per mg of protein, was similar with either cofactor. Km values for NADPH and NADH were 3 and 150 microM respectively. Optimal rates with either NADPH or NADH were found in the pH range 6.5-7.4. The enzyme also showed some reactivity towards hydroxypyruvate with rates less than 2% of those observed for glyoxylate. Results of immunological studies, using antibodies prepared against either glyoxylate reductase or spinach peroxisomal hydroxypyruvate reductase, suggested substantial differences in molecular structure of the two proteins. The high rates of NADPH(NADH)-glyoxylate reductase in crude leaf extracts of spinach, wheat and soya bean (30-45 mumol/h per mg of chlorophyll) and its strong affinity for glyoxylate suggest that the enzyme may be an important side component of photorespiration in vivo. In leaves of nitrogen-fixing legumes, this reductase may also be involved in ureide breakdown, utilizing the glyoxylate produced during allantoate metabolism.

scholarly journals Purification and characterization of hydroxypyruvate reductase from a serine-producing methylotroph, Hyphomicrobium methylovorum GM2

1990 ◽  
Vol 190 (2) ◽  
pp. 279-284 ◽  
Author(s):  
Yoshikazu IZUMI ◽  
Toyokazu YOSHIDA ◽  
Hiroshi KANZAKI ◽  
Shin-ichiro TOKI ◽  
Silvia Susana MIYAZAKI ◽  
...  
Keyword(s):  
Purification And Characterization ◽  
Hydroxypyruvate Reductase

NADP+-isocitrate dehydrogenase in germinating cucumber cotyledons: Purification and characterization of a cytosolic isoenzyme

1996 ◽  
Vol 98 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Stefania Canino ◽  
Barbara Nieri ◽  
Laura Pistelli ◽  
Amedeo Alpi ◽  
Luigi De Bellis
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Purification And Characterization ◽  
Cucumber Cotyledons

scholarly journals Purification and characterization of a novel NADPH(NADH)-dependent hydroxypyruvate reductase from spinach leaves. Comparison of immunological properties of leaf hydroxypyruvate reductases

1988 ◽  
Vol 250 (1) ◽  
pp. 145-152 ◽  
Author(s):  
L A Kleczkowski ◽  
D D Randall
Keyword(s):  
Substrate Inhibition ◽  
The Novel ◽  
Purification And Characterization ◽  
Leaf Extracts ◽  
Hydroxypyruvate Reductase ◽  
Dependent Activity ◽  
Immunological Comparison ◽  
Spinach Leaf ◽  
Ph Range

A novel hydroxypyruvate reductase preferring NADPH to NADH as a cofactor was purified over 1500-fold from spinach leaf extracts. The enzyme was an oligomer of about 70 kDa, composed of two subunits of 38 kDa each. The Km for hydroxypyruvate (with NADPH) was about 0.8 mM in the pH range 5.5-6.5, and 0.3 mM at pH 8.2. The Vmax. was highest in the pH range 5.5-6.5 and decreased by about 65% at pH 8.2. Above pH 6.0, the enzyme was prone to a strong substrate inhibition by hydroxypyruvate. The reductase could use glyoxylate as an alternative substrate, with rates up to one-quarter of those with hydroxypyruvate. This glyoxylate-dependent activity preferred NADPH to NADH as a cofactor. Rabbit antibodies prepared against NADPH(NADH)-hydroxypyruvate reductase were highly specific for this enzyme and did not cross-react with peroxisomal NADH(NADPH)-dependent hydroxypyruvate reductase, as found by Western immunoblots of proteins from leaf extracts of spinach, pea and wheat. Antibodies raised against purified NADH(NADPH)-hydroxypyruvate reductase were also highly specific, recognizing only their own antigen. To our knowledge, this is the first report in the literature of the occurrence of NADPH(NADH)-hydroxypyruvate reductase in leaves, and the first to provide immunological comparison of leaf hydroxypyruvate reductases. Because of the relatively high rates of the novel reductase in leaf extracts (at least 20 mumol/h per mg of chlorophyll), this enzyme might be an important side-component of the glycollate pathway (photorespiration), possibly utilizing hydroxypyruvate ‘leaked’ from peroxisomes, and thus contributing to the glycerate pool derived from glycollate. Because of the glyoxylate-dependent activity, the enzyme may also contribute to glycollate formation in leaves.

Purification and characterization of phosphoglucomutase from peas

1994 ◽  
Vol 92 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Cynthia M. Galloway ◽  
W. Mack Dugger
Keyword(s):  
Purification And Characterization
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