Studies on the Metabolism of L‐Phenylalanine by Tetrahymena performs W*

Abstract

The effect of a series of phenylalanine‐ or tyro‐sine‐containing peptides and derivatives on the oxygen consumption of washed Tetrahymena performers W cells was determined. Peptides gave greater stimulation of oxygen uptake than phenylalanine or tyrosine alone. Intermediary reaction products of phenylalanine metabolism were not oxidized, nor were derivatives of phenylalanine in which the amino group was blocked. The action of several tyrosine or phenylalanine ant metabolites was determined. It was demonstrated that extra‐cellular hydrolysis of glycyl‐L‐phenylalanine and alanyl‐L‐phenylalanine took place when these peptides were incubated with washed protozoa.

In Memoriam: Herbert J. Eichel (1924–2017) a Passion for Discovery

“…It revealed unusual L‐phenylalanine and L‐tyrosine activity (Roth et al. ), and a subsequent publication describing the mechanism for oxidation of these amino acids and their derivatives (Roth and Eichel ). Years later another study enhanced this work using strain WH6 (Perlish and Eichel ).…”

“…While pursuing the unique role of L‐lactate in Tetrahymena , he discovered and partially characterized an unusual L‐lactate oxidase, which catalyzes the reaction: L‐lactate + O 2 → pyruvate + H 2 O 2 (Eichel 1960c; Eichel and Rem ,b, ; Roth and Eichel ). Subsequent findings from his laboratory showed that the lactate enzyme may be a general L‐α‐hydroxy acid oxidase, with greater specificity toward α‐hydroxybutyrate than lactate (Eichel 1964b; Eichel et al.…”

“…). In addition, they first determined the intracellular distribution of many enzymes in T. pyriformis homogenates by differential centrifugation, including succinate dehydrogenase, fumarase, aconitase, and many purine‐ and pyrimidine‐metabolizing enzymes (Eichel 1954b, ; Roth and Eichel ).…”

Evolutionary Trends in Heteroptera

“…REMOLD ?^the^W» that the secretions might act also as pheromones and he «**^%Z^ secondary reservoirs in the males of some Lygaeidae as ^^0^^ when littfe is discharged. Accurate behavioral stud-^ 8U^^^£ some patterns in courtship suggest ^^^^^S^^to proof for pheromonal P-^.^ (CARAYON, the male only (some Anthocondae (CARAYON 19M) P heteropterous 1948), Lethocerus indicus (^^^^^^e^!^ (ROTH, 1961; glands have been suggested, ^/ ung^^ TI M 0NIN , 1961), producing "£?^X^°»* ** °" *"*""* water surface (BRINKHURST, 1960, provided omy w experiments).…”