NADP+ reduction by human lymphocytes

A. Klein, A. W.L. Chan, B. U. Caplan, A. Malkin

Research output: Contribution to journalArticlepeer-review

Abstract

The hexose monophosphate shunt (HMPS) is known to be responsible for the reduction of NADP+ by lymphocytes. We tried to find other enzymatic systems that might provide the lymphocytes with NADPH. By measuring the absorbance at 340 nm we noted that the addition of NADP+ to a preparation of disrupted lymphocytes resulted in the formation of NADPH at a rate of 4 nmol/106 cells per min. This phenomenon could not be changed by negative feedback inhibition of HMPS, and could not be attributed to the low concentration of glucose, glucose-6-phosphate (G-6-P) and isocitrate found in the cell preparation (NADP+-dependent isocitrate dehydrogenase in addition to HMPS NADP+ reducing enzymes was found to be present in lymphocytes). Because of the activity of a NADP+-dependent lactate dehydrogenase, pyruvate oxidized the NADPH as it was being formed. Here we demonstrate the presence of an unknown NADP+ reducer in lymphocytes which seems to play an additional role to HMPS in NADP+ reduction by lymphocytes. NADP+-dependent lactate dehydrogenase may play a role in regulating the NADP+/NADPH ratio.

Original languageEnglish
Pages (from-to)170-173
Number of pages4
JournalClinical and Experimental Immunology
Volume82
Issue number1
DOIs
StatePublished - 1990
Externally publishedYes

Keywords

  • NADP
  • NADPH
  • hexose monophosphate shunt
  • lymphocytes
  • pyruvate

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