Inhibitory action

Phenazine-l-carboxamide (137) is known as oxychlororaphine and has been isolated from cultures of Pseudomonas chlororaphisit has some limited inhibitory properties, but the inhibitory action of phenazines is generally disappointing. Some phenazine derivatives have insecticidal properties thus, phenazine itself has been found to be toxic to the clothes moth, the Hawaiian beet webworm, the rice weevil and larva of the codling moth, but under trial conditions its toxicity to plant material, as evidenced by severe burning of foliage, was found to be too high to make it of practical value. 

In more recent times chemically defined basal media have been elaborated, on which the growth of various lactic acid bacteria is luxuriant and acid production is near-optimal. The proportions of the nutrients in the basal media have been determined which induce maximum sensitivity of the organisms for the test substance and minimize the stimulatory or inhibitory action of other nutrilites introduced with the test sample. Assay conditions have been provided which permit the attainment of satisfactory precision and accuracy in the determination of amino acids. Experimental techniques have been provided which facilitate the microbiological determination of amino acids. On the whole, microbiological procedures now available for the determination of all the amino acids except hydroxy-proline are convenient, reasonably accurate, and applicable to the assay of purified proteins, food, blood, urine, plant products, and other types of biological materials. On the other hand, it is improbable that any microbiological procedure approaches perfection and it is to be expected that old methods will be improved and new ones proposed by the many investigators interested in this problem. 

Philleo et al. (29) recently confirmed the inhibitory action of methylene dioxyphenyl groups on biological oxidations in insects, including epoxidation and hydroxylation of certain compounds. 

Protoanemonin, which has been isolated from Anemone pulsatilla and Ranunculus spp., was reported to inhibit root growth by slowing down metabolism and blocking mitosis 35). Erickson and Rosen 35) observed cytological effects in corn root tips at concentrations of 10M and lower. Cells undergoing division appeared to accumulate in the interphase or prophase stages. Metaphase, anaphase, and telophase stages were not observed. Cytoplasmic and vacuolar structures were disturbed and the presence of mitochondria could not be demonstrated in treated tissue. Thimann and Bonner 141) reported that protoanemonin was 10 to 30 times more inhibitory than coumarin in coleoptile and split pea stem tests, and that BAL prevented the inhibitory action. 

Relatively few sites of growth-modifying or growth-inhibitory action have been identified at the cellular and molecular level. Consequently, the exact action of, and relationships between, auxins, gib-berellins, kinins, and growth inhibitors remain to be elucidated. 

The intracellular pH can also regulate the exchanger. [H+] strongly inhibits NCX activity under steady-state conditions, in fact, reduction in [pH] values, as little as 0.4, can induce a 90% inhibition of NCX activity. Such inhibitory action depends on the presence of intracellular Na+ ions, hence, the action exerted by H+ ions is pathophysiologically relevant with regards to brain and heart ischemia. 

Ribosomal Protein Synthesis Inhibitors. Figure 3 The chemical structure of tetracycline and possible interactions with 16S rRNA in the primary binding site. Arrows with numbers indicate distances (in A) between functional groups. There are no interactions obseived between the upper portion of the molecule and 16S rRNA consistent with data that these positions can be modified without affecting inhibitory action (from Brodersen et al. [4] with copynght permission). 

Several mono-carba-oligosaccharidic alpha amylase inhibitors, such as acarbose and its homologs, amylostatins, trestatins, oligostatins, adipo-sins, and so on, have been isolated from cultures of micro-organisms, and considerable interest in the biochemistry and chemistry of this class of inhibitors has been stimulated. The characteristic core-structure for inhibitory action is composed of a trihydroxy(hydroxymethyl)cyclohexene moiety and a 4-amino-4,6-dideoxy-D-glucopyranose moiety, bonded by way of an imino linkage at the allylic position. A similar structural unit has been found in the antibiotic validamycins. 

Figure 51-7. Scheme of sites of action of streptokinase, tissue plasminogen activator (t-PA), urokinase, plasminogen activator inhibitor, and Kj-antiplasmin (the last two proteins exert inhibitory actions). Streptokinase forms a complex with plasminogen, which exhibits proteolytic activity this cleaves some plasminogen to plasmin, initiating fibrinolysis. 

Glaum SR, Miller RJ, Hammond DL (1994) Inhibitory actions of delta 1-, delta 2-, and mu-opioid receptor agonists on excitatory transmission in lamina II neurons of adult rat spinal cord. 

Sulphonamides are structural analogues of PABA. They competitively inhibit the incorporation of PABA into dihydropteroic acid and there is some evidence for their incorporation into false folate analogues which inhibit subsequent metabolism. The presence of excess PABA will reverse the inhibitory action of sulphonamides, as will thymine, adenine, guanine and methionine. However, these nutrients are not normally available at the site of infections for which the sulphonamides are used. 

Luciferase assay. In this technique, firefly luciferase is used to measure small amounts of adenosine triphosphate (ATP) in a bacterial culture, ATP levels being reduced by the inhibitory action of aminoglycoside antibiotics. This method may find more application in the future as more active and reliable luciferase preparations become available. 

Glycine is the simplest of all amino acids. It is involved in many metabolic pathways, is an essential component of proteins, and is found throughout the brain. A neurotransmitter role for glycine was first identified in the spinal cord, where it was found to be differentially distributed between dorsal and ventral regions and shown to cause hyperpolarisation of motoneurons (Werman et al. 1967). This inhibitory action of glycine is distinct from its... 

The mu, delta and kappa opioid receptors are coupled to G° and G proteins and the inhibitory actions of the opioids occur from the closing of calcium channels (in the case of the K receptor) and the opening of potassium channels (for /i, d and ORL-1). These actions result in either reductions in transmitter release or depression of neuronal excitability depending on the pre- or postsynaptic location of the receptors. Excitatory effects can also occur via indirect mechanisms such as disinhibition, which have been reported in the substantia gelatinosa and the hippocampus. Flere, the activation of opioid receptors on GABA neurons results in removal of GABA-mediated inhibition and so leads to facilitation. 

FUJITA H, YAMAGAMi T (2001) Fermented soybean-derived Touchi-extract with anti-diabetic effect via alpha-glucosidase inhibitory action in a long-term administration study with KKAy mice. Life Sci. 70 219-27. 

We succeeded in showing that recycling of the enzyme was indeed possible in our IL solvent system, though the reaction rate gradually dropped with repetition of the reaction process. Since vinyl acetate was used as acyl donor, acetaldehyde was produced hy the hpase-catalyzed transesterification. It is well known that acetaldehyde acts as an inhibitor of enzymes because it forms a Schiff base with amino residue in the enzyme. However, due to the very volatile nature of acetaldehyde, it easily escapes from the reaction mixture and therefore has no inhibitory action on the lipase. However, this drop in reactivity was assumed to be caused by the inhibitory action of acetaldehyde oligomer which had accumulated in the [bmim][PFg] solvent system. In fact, it was confirmed that the reaction was inhibited by addition of acetaldehyde trimer. =... 

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