A-Aminooxyacetic acid

D-phenylalanine, the sterioisomer of the naturally occurring L-phenylalanine, inhibits the PAL activity. Szkutnicka and Lewak (18) found that the application of this compound to germinating seeds caused an increase in the PAL level. They attributed this to the decrease in the production of cinnamic acid and compounds derived therefrom. Similar results have been obtained by Amrhein and Gerhardt (19) with the PAL-inhibitors, L-a-aminooxy-8-phenylpropionic acid and a-aminooxyacetic acid on gherkin seedlings. They found that the synthesis of hydroxycinnamic acids was inhibited and that the PAL level increased. This increase was suppressed when tr<2 s-cinnamic acid was applied. 

This indicates that repression by accumulating products may play a regulatory role in the cinnamic acid metabolism of Cucumis, In other organisms, however, e.g., in Fagopyrum esculen-turn, this regulatory principle could not be substantiated. Here PAL activity after illumination showed a similar time course with and without a-aminooxyacetic acid. 

Tiburzy (22,31) obtained similar results by application of the PAL inhibitor aminooxyacetic acid (AOA). However, AOA does not specifically inhibit PAL (99), and PAL is not only involved in lignin biosynthesis (100). Thus, AOA and the related inhibitor aminooxyphenyl propionic acid (AOPP) (101,102) inhibit the biosynthesis of lignin (103,104), anthocyanins (105), other flavonoids (106), and conjugates of cinnamic acids (107) via PAL, as well as ethylene (108-110) via a pyridoxal phosphate dependent enzyme (110,111). In view of the possible function of phenolic compounds as phytoalexins (21,112,113) and the well documented role of ethylene in some resistance reactions (114-116), the above cited experiments with AOA (22,... 

A solution of the step 1 product (0.023 mol) dissolved in 100 ml of chloroform was treated with Boc-aminooxyacetic acid (1.5 eq) and l-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide (1.5 eq) and then stirred overnight under nitrogen. The mixture was concentrated, the residue was chromatographed as described in step 1, and 4.6 g of product isolated. 

Similar trends were noted in fasted male Sprague-Dawley rats following a 4-h inhalation exposure to 180-200 ppm [720-800 mg/m ] vinylidene chloride (Cavelier et al., 1996). Analysis of urine and serum for biochemical markers of toxicity 24 h after exposure revealed increased toxicity following vinylidene chloride exposure. Levels of marker enzymes were similar to control values following pretreatment with aminooxyacetic acid. No effect was noted on vinylidene chloride toxicity following acivicin treatment and only slight increases in vinylidene chloride toxicity were obsen ed following methimazole pretreatment. 

There exists a large body of literature on the turnover of GABA in brain In this review I have recommended the use of specific GABA-T inhibitors, such as 7-vinyl-GABA, gabaculine, and aminooxyacetic acid, that can be administered either systemically or intracerebrally... 

Walaas I. and Fonnum F (1980) Biochemical evidence for glutamate as a transmitter in hippocampal efferents to the basal forebrain and hypothalamus in rat brain Neuroscience 5, 1691-1698 Wallach D P. (1961) Studies on the GABA pathway. I. The inhibition of 7-aminobutyric acid-a-ketoglutanc acid transaminase in vitro and in vivo by U-7524 (aminooxyacetic acid) Biochem Pharmacol. 5, 323-331. 

The inhibitory potencies of the compounds, along with those of several GAD inhibitors from the literature, are summarized in Table II. Reasonable agreement was found between the bacterial and insect enzymes. Toxic compounds were good inhibitors of GAD, in general, although aminooxy acids 1 and 2 (Table II) were potent inhibitors without being very toxic. A previous observation that insect GAD is not inhibited by aminooxyacetate (15) may be explained by the use of different enzyme preparations in the two studies. In the present work it was found that GAD in a crude muscle homogenate was not consistently inhibited by aminooxyacetate. It was this observation that led to the above purification protocol. 

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