Phe— Pho

The chiral ligands (R)-Val-Phos(17a) and (R)-Phe-Phos (17b) have been synthesized from (S)-valine and (S)-phenylalanine, respectively, in an industrial laboratory 43). 

Figure 11.9 Schematic view of the experimental strategy for carrying out poly(Phe) synthesis in POPC liposomes, (i) Freeze-thaw (x 7) solution containing t-RNAP , poly(U), Phe, ATP, GTP, Mg(OAc)2, NH4CI, spermine, spermidine, phos-phoenolpyruvate. (ii) Soution containing pyruvate kinase, 100 000 g supernatant enzymes, 308 and SOS ribosomal subunits, (iii) 1. Free-thaw (x3) 2. Brief extrusion 3. Addition of EDTA (final concentration = 35 mM. (iv) Withdrawl of aliquots at indicated time and cold TCA precipitation. Analysis of the radioactivity remaining on the glass filter by p-scintillation counting. (Modified from Oberholzer et al, 1999.)...

As mentioned in the introductory section, arynes behave as soft acids . Therefore, the relative reactivity of a nucleophile should be governed by basicity as well as polarizability. The following gradations, established through competitive reactions of arynes with different nucleophiles, are more or less in line with this expectation.1 (i) BuLi > PhSLi > PhNMeLi > PhGaCLi > ROLi > ArOLi, for 9,10-phe-nanthryne in ether (ii) PhS- > Ph3C > PhC=C > enolates > PhO- > RO" > I, CN, for benzyne in liquid ammonia (iii) I- > Br > Cl- > EtOH for benzyne in alcohol. 

Peptides that display a terminally located aldehyde function in their structure constitute another group of modified peptide enzyme inhibitors. The sequence benzyloxycarbonyl-Pro-Phe-CHO fulfils the known primary and secondary specificity requirements of chymotrypsin and has been found to be a potent reversible inhibitor of this proteolytic enzyme (Walker et al. 1993). Further, protease inhibitors comprising terminally located aldehyde function are antipain, leupeptin, chymostatin, and elastatinal. In addition, also phos-phoramidon, bestatin, puromycin, and amastatin represent modified peptides which can reversibly inhibit enzymes. 

Noort et al. (53) recently demonstrated that phosgene binds effectively to albumin and hemoglobin upon in vitro exposure of human blood to [14C]phos-gene (53). Upon Pronase digestion of globin, one of the adducts identified was the pentapeptide 0=C-(Val-Leu)-Ser-Phe-Ala, representing amino acids 1-5 of a-globin, with a hydantoin function between the N-terminal valine and leucine. This adduct... 

Unter dem katalytischen EinfluB von Amin-Hydrochloriden reagieren Hexaalkyl-phos-phorigsaure-triamide mit Benzaldehyd bei 70° (4—5 Stdn.) zu Dialkylamino-phe-nyl-methanphosphonsaure-diamidenMI ... 

In a very imaginative piece of research Frost and coworkers have developed a plasmid-based method for synthesizing aromatic amino acids, by incorporating the genes that code for the enzymes that perform the series of conversions from D-fructose-6-phosphate to D-erythrose-4-phosphate to 3-deoxy-D-arabinoheptulosonic acid-7-phos-phate (DAHP) near each other on a plasmid that can be transformed in E. coli. The enzymes are the thiamin diphosphate-dependent enzyme transketolase in the nonoxida-tive pentose shunt and DAHP synthase. The DAHP is then converted to the cyclic dehydroquinate, a precursor to all aromatic amino acids L-Tyr, L-Phe and L-Trp165,166 (equation 27). 

Enkephalinase Zn(II)(His)2(Glu) (hydrolyzes neuropeptides) Analgesics (thiorphan, phos-phoryl-Leu-Phe)... 

TABLE 5. Hydrogen donating ability of tocopherol and related antioxidants to a substituted phe-noxyl radical (PhO ) ... 

Bartlett and Marlowe (153) designed a series of five phosphonamidate analogs of the peptide carbobenzoxy-Gly-Leu-X (X = NH2, Gly, Phe, Ala, Leu), where a -POz-NH- replaces the Gly-Leu peptide bond, and showed that these compounds were potent transition-state analog inhibitors of the zinc endopeptidase thermolysin. They also synthesized the corresponding phos-phonate analogs, where the -NH- (13A) is replaced by -O- (I3B). The... 

Figure 1. Diagrammatic representation of olfactory receptor cell activity during odour stimulation. The spot size is roughly proportional to spike frequency (spike/min). Receptor cells taken at random from the epithelium of a frog are identified hy a serial number in the left column (60 in all). ACE - acetophenone, ANI - anisole, BUT - n-butanol, CAM - DL-camphor, CDN - cyclodecanone, CIN - cineole, CYM, p-cymene, DCT D-citronellol, HEP - n-heptanol, ISO - isoamylacetate, IVA - isovaleric acid, LIM -D-linonene, MAC - methyl-amylketone, MEN - L-menthol, PHE - phenol, PHO -thiophenol, PYR - pyridine, THY - thymol, XOL - cyclohexanol, XON - cyclohexanone. (From Sicard Holley [7]).

Phenylthiol diazoacetate, 40 Phe-tRNA, 625, 627-029, 707 Phe-tRNA , 75, 638, 640 Phosphoenolpyruvate-uridine-5 -diphos-pho-A -aeetyl-2-amino-2-deoxygIu-cose 3-0-pyruvyltransferase, 543 Phosphofructokinase, 90 binding site, 76... 

In other experiments we used mainly spleen as the activity was the highest in this tissue. We observed that in spleen, like in retina the enzymic activity was located in the cytosol obtained by centrifugating at 105.000 g for an hour an homogenate prepared in phos-phe buffered sucrose and that the pH optimum for this enzyme was around 7, which means similar to that observed for the enzyme from retina 8. 

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