Photoinactivation of peptide transport in Saccharomyces cerevisiae

Abstract

Oligopeptides and dipeptides are transported into Saccharomyces cerevisiae by a carrier-mediated system. In the dark, leucyl-p-nitroanilide (Leu-p-NA) and leucyl-leucyl-4-azido-2-nitrophenylalanine [Leu-Leu-Phe-(4N3,2NO2)] are competitive inhibitors of peptide transport by S. cerevisiae cells. The photolysis of yeast cells in the presence of Leu-p-NA or Leu-Leu-Phe(4N3,2NO2) at 350 nm results in an irreversible inactivation of peptide transport. Protection against this inactivation is afforded by an excess of trimethionine, a transported peptide. Photolysis with Leu-p-NA or Leu-Leu-Phe(4N3,2NO2) does not affect amino acid or sugar transport, and cell viability is maintained throughout the irradiation procedure. A 5-min irradiation of S. cerevisiae with 2.4 microM Leu-p-NA or 15 microM Leu-Leu-Phe(4N3,2NO2) causes 50% inhibition of trimethionine uptake. p-Nitroaniline, a possible hydrolysis product generated from Leu-p-NA by cellular peptidase activity, has no effect on peptide transport. An exogenous energy source is not required for photoinactivation. The results suggest that a component(s) of the peptide transport system of S. cerevisiae is irreversibly modified by photolysis with Leu-p-NA or Leu-Leu-Phe-(4N3,2NO2) and provide the first example of the use of amino acid p-nitroanilides as photoaffinity labels.

Pharmaceutical and pharmacological importance of peptide transporters

“…When working on peptide transport in Saccharomyces cerevisiae, Jeffrey M. Becker observed that leucyl-p-nitroanilide is a competitive inhibitor of peptide transport and used it as a photoaffinity label for the carrier protein (Becker et al 1982). Daniel & Adibi (1994) found that amino acid 4-nitroanilides are recognized by mammalian renal peptide transporters with high affinity.…”

Prostaglandins and congeners. 22. Synthesis of 11-substituted derivatives of 11-deoxyprostaglandins E1 and E2. Potential bronchodilators

“…The polar epimer 27 was obtained as an oil (63 mg, 6%): NMR (acetone-d6) 5.66 (m, 2 H, CH=CH), 4.05 (m, 1 H, C-15 ), 3.90 (q, 1 H, C-ll H). The mobile epimer 28 was obtained as an oil (152 mg, 15%): NMR (acetone-d6) 6 5.66 (m, 2 H, CH=CH), 4.05 (m, 1 H, C-15 H), 3.90 (q, 1 H, C-ll H). In addition fractions consisting of a mixture of the epimers, Rf 0.38 and 0.50 (1% HOAc in EtOAc), were obtained (100 mg, 10%).…”

“…Found: 481.3208). " 3.38 (s, 1 H, OH), 1.03 [t,6 H, N(C773CH2)2], kk S: caled, 6.49; found,5.86.Derivatives of 11-Deoxyprostaglandins E¡…”