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Proline‐Dehydrogenase from Pumpkin ( Cucurbita moschata ) Cotyledons
Author(s) -
RENA ALEMAR B.,
SPLITTSTOESSER WALTER E.
Publication year - 1974
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1974.tb03749.x
Subject(s) - proline dehydrogenase , cucurbita moschata , proline , dehydrogenase , nad+ kinase , cucurbita , chemistry , biochemistry , enzyme , amino acid , pathology , medicine , alternative medicine
A NAD specific proline‐dehydrogenase was found in pumpkin ( Cucurbita moschata Poir. cv. Dickinson Field) which oxidized proline to Δ 1 ‐pyrroline‐5‐carboxylate. NADP did not substitute for NAD and L‐proline‐methyl‐ester and thiazolidine‐4‐carboxylate were substrates in the reaction, at a rate of 107% and 33% respectively, of the rate with L‐proline. Pumpkin cotyledons contained the bulk of the enzyme activity with 90% of the activity being in the soluble fraction. Proline‐dehydrogenase, which was not treated at high temperature, was stable at –10°C for 4 months in the presence of high ammonium sulfate concentration. The Michaelis constant for NAD was 2.2 m M and for L‐proline was 2.5 m M . At 5 m M NADP, a 40% non‐competitive inhibition of proline‐dehydrogenase was obtained, while 50 μ M NADP was sufficient to induce 20% inhibition.