Inhibition of NADP-dependent dehydrogenases by modified products of NADPH
When NADPH was incubated at neutral pH, a modified product which had no absorbancy at 340 nm, but exhibited a slight shoulder in the region of 280–300 nm with maximum absorbancy at 266 nm, was produced. Phosphate accelerated the conversion. This compound was tentatively designated as NADPH-X. At aci...
Saved in:
Published in | Archives of biochemistry and biophysics Vol. 169; no. 1; pp. 298 - 303 |
---|---|
Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
01.07.1975
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | When NADPH was incubated at neutral pH, a modified product which had no absorbancy at 340 nm, but exhibited a slight shoulder in the region of 280–300 nm with maximum absorbancy at 266 nm, was produced. Phosphate accelerated the conversion. This compound was tentatively designated as NADPH-X. At acidic pH, NADPH was rapidly converted to the primary acid-modified product which had a similar, but not identical, absorption spectrum to that of NADPH-X, and it was gradually converted to the secondary acid-modified product which exhibited a distinctive absorption spectrum with a maximum at 261 nm. NADPH-X strongly inhibited human glucose 6-phosphate dehydrogenase, human 6-phosphogluconate dehydrogenase, and yeast glucose 6-phosphate dehydrogenase. The primary acid-modified product inhibited human 6-phosphogluconate dehydrogenase, but human and yeast glucose 6-phosphate dehydrogenases were not sensitive to this compound. The secondary acid-modified product inhibited the three dehydrogenases. The mode of the dehydrogenase inhibition by these compounds was competitive with NADP. Potential physiologic role of NADPH-X was discussed. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0003-9861 1096-0384 |
DOI: | 10.1016/0003-9861(75)90344-6 |