Amino indicator

These are the structural units of protein. The term amino indicates the presence of the NHj group-a base-while the term acid indicates the presence of the COOH groups or carboxyl group-an acid. Since all amino acids possess this unique chemical feature of containing both an acid and a base, they are capable of both acid and base reactions in the body. Thus, they are said to be amphoteric. There are 22 amino acids. 

Figure C2.5.10. The figure gives tire foldability index ct of 27-mer lattice chains witli sets containing different number of amino acids. The sets are generated according to scheme described in [27], The set of 20 amino acids is taken as a standard sample. Each sequence witli 20 amino acids is optimized to fulfil tire stability gap [5]. The residues in tire standard samples are substituted witli four different sets containing a smaller number of amino acids [27]. The foldability of tliese substitutions is indicated by tire full circles. The open diamonds correspond to tire sequences witli same composition. However, tire amino acids are chosen from tire reduced representation and tire resultant sequence is optimized using tire stability gap [5].

It can be seen from Table 2 that the intrinsic values of the pK s are close to the model compound value that we use for Cys(8.3), and that interactions with surrounding titratable residues are responsible for the final apparent values of the ionization constants. It can also be seen that the best agreement with the experimental value is obtained for the YPT structure suplemented with the 27 N-terminal amino acids, although both the original YPT structure and the one with the crystal water molecule give values close to the experimentally determined one. Minimization, however, makes the agreement worse, probably because it w s done without the presence of any solvent molecules, which are important for the residues on the surface of the protein. For the YTS structure, which refers to the protein crystallized with an SO4 ion, the results with and without the ion included in the calculations, arc far from the experimental value. This may indicate that con-... 

In the example of Figure 2-5, the compound has the trivial name phenylalanine but the lUPAC name is 2-amino-3-phenylpropanoic acid, which indicates a carbon... 

Besides specifications on atoms, bonds, branches, and ring closure, SLN additionally provides information on attributes of atoms and bonds, such as charge or stereochemistry. These are also indicated in square [ ] or angle < > brackets behind the entity e.g., trans-butane CH3CH=[s=t]CHCH3). Furthermore, macro atoms allow the shorthand specification of groups of atoms such as amino adds, e.g., Ala, Protein2, etc. A detailed description of these specifications and also specifications for 2D substructure queries or combinatorial libraries can be found in the literature [26]. 

It should be noted that only representative substances are indicated in the above list. Substituted derivatives of the compounds in most classes may be encountered, e.g., nitrobenzoic acid in the aromatic carboxylic acids (p. 347). This acid will contain CH(0)N, but the salient properties are still those of a carboxylic acid, CH(0), Section 14, although the properties of an aromatic nitro-compound (e.g.y reduction to an amino-compound) will also be evident. 

To 5 ml. of water add 1-2 drops of the amine if the amine does not dissolve, add a drop or two of concentrated hydrochloric acid. Add 0-5-1 ml. of this amine solution to 2-3 ml. of the reagent an almost immediate precipitate indicates the presence of a primary amine. A slight turbidity indicates the presence of a primary amine as an impurity. (Primary aromatic amines generally require 2-3 minutes for the test. Urea and other amides, as well as amino acids, do not react.)... 

The amino add analysis of all peptide chains on the resins indicated a ratio of Pro Val 6.6 6.0 (calcd. 6 6). The peptides were then cleaved from the resin with 30% HBr in acetic acid and chromatogra phed on sephadex LH-20 in 0.001 M HCl. 335 mg dodecapeptide was isolated. Hydrolysis followed by quantitative amino acid analysis gave a ratio of Pro Val - 6.0 5.6 (calcd. 6 6). Cycll2ation in DMF with Woodward s reagent K (see scheme below) yielded after purification 138 mg of needles of the desired cyc-lododecapeptide with one equiv of acetic add. The compound yielded a yellow adduct with potassium picrate, and here an analytically more acceptable ratio Pro Val of 1.03 1.00 (calcd. 1 1) was found. The mass spectrum contained a molecular ion peak. No other spectral measurements (lack of ORD, NMR) have been reported. For a thirty-six step synthesis in which each step may cause side-reaaions the characterization of the final product should, of course, be more elaborate. 

The "zip-reaction (U. Kramer, 1978, 1979) leads to giant macrocycles. Potassium 3- ami-nopropyl)amide = KAPA ( superbase ) in 1,3-diaminopropane is used to deprotonate amines. The amide anions are highly nucleophilic and may, for example, be used to transam-idate carboxylic amides. If N- 39-atnino-4,8,12,16,20,24,28,32,36-nonaazanonatriacontyl)do-decanolactam is treated with KAPA, the amino groups may be deprotonated and react with the macrocyclic lactam. The most probable reaction is the intramolecular formation of the six-membered ring intermediate indicated below. This intermediate opens spontaneously to produce the azalactam with seventeen atoms in the cycle. This reaction is repeated nine times in the presence of excess KAPA, and the 53-membered macrocycle is formed in reasonable yield. 

To sum up, spectroscopic data indicate the amino" form (10) is predominant when R is a hydrogen atom or an alkyl group, while the imino form (11) is predominant when R is an aryl group (Scheme 66). 

The mixed 2-chloro-5-bromothiazole has been obtained from 2-amino-5-bromothiazole, as previously indicated (75). 

It IS understood that a amino acids occur as their l stereo isomers unless otherwise indicated The d notation is explicitly shown when a D amino acid is present and a racemic amino acid is identified by the prefix dl... 

As shown in Figure 45.1, the bases appear in complementary pairs, A with T and G with C in this particular example, the sequence for one strand of DNA is A-T-C-G-T- while the other strand is -T-A-G-C-A-. The sequences of the bases attached to the sugar-phosphate backbone direct the production of proteins from amino acids. Along each strand, groups of three bases, called codons, correspond to individual amino acids. For example, in Figure 45.1, the triplet CGT, acting as a codon, would correspond to the amino acid serine. One codon, TAG, indicates where synthesis should begin in the DNA strand, and other codons, such as ATT, indicate where synthesis should stop. 

Fig. 3. Human CG, hLH, and equine CG (eCG) P-subunits. Amino acid numbeiing is relative to maximum homology between the three subunits. Consensus glycosylation sites ate at Asn-13 and 30. = same amino acid as hCG/3. Underlined Asn residues indicate attachment of N-linked carbohydrate chains. Serines at positions 121, 127, 132, and 138 of hCGP are underlined to indicate sites of O-linked carbohydrate attachment. Residues 115—118,...

Fig. 1. Stmcture of oxytocin and arginine vasopressin. Numbers indicate approximate location of amino acids sequences found in Table 1. A, oxytocin B,...

Fig. 2. X-ray structure of dearniaooxytociii (a) space-filling model (b) equivalent stick model. Numbers and amino acids refer to positions indicated in...

Although FeMo-cofactor is clearly knpHcated in substrate reduction cataly2ed by the Mo-nitrogenase, efforts to reduce substrates using the isolated FeMo-cofactor have been mosdy equivocal. Thus the FeMo-cofactor s polypeptide environment must play a critical role in substrate binding and reduction. Also, the different spectroscopic features of protein-bound vs isolated FeMo-cofactor clearly indicate a role for the polypeptide in electronically fine-tuning the substrate-reduction site. Site-directed amino acid substitution studies have been used to probe the possible effects of FeMo-cofactor s polypeptide environment on substrate reduction (163—169). Catalytic and spectroscopic consequences of such substitutions should provide information concerning the specific functions of individual amino acids located within the FeMo-cofactor environment (95,122,149). 

Fig. 5. Schematic diagram of the presumed arrangement of the amino acid sequence for the 5-opioid receptor, showing seven putative transmembrane segments three intracellular loops, A three extracellular loops, B the extracellular N-terrninus and the intracellular C-terrninus, where (0) represents amino acid residues common to ] -, 5-, and K-receptors ( ), amino acid residues common to all three opioid receptors and other neuropeptide receptors and (O), other amino acids. Branches on the N-terruinal region indicate possible glycosylation sites, whereas P symbols in the C-terminal region indicate...

Synthetic Applications. Oxazolines, which ate synthesized as indicated above, have been utilized in many different appHcations (25). When used in resin formulations, AMP, AEPD, and TRIS AMINO can incorporate the oxazoline stmeture into the polymer stmeture (26). Because they ate polyols, both AEPD and TRIS AMINO can be used in polyester resin modification. Oxazoline alkyd films ate characterized by improved performance, particularly salt-spray resistance and gloss (see Alkyd resins Coatings, special purpose, high performance). 

Feeding standards, which have been instituted nationally, indicate the amount of the essential amino acids (together with other nutrients) for the rational breeding of domestic animals. The feeding standards of the National Research Council (NRC) of the United States and Agricultural Research Council (ARC) of the United Kingdom are well known (the former indicates the minimal amount and the latter shows the recommended amount). 

Fig. 2. Amino acid analysis by automated ion-exchange chromatography. Standard column, 4.6 mm ID x 60 mm Ninhydrin developer. Computer print out indicates retention time (RT), height and area of peaks, and the ratio of the height of an amino acid in the sample to the height of a standard amino acid.

The major use of this compound is in the production of mordant and acid dyes. 2-Amino-4-nitropheno1 also has found limited use as an antioxidant and light stabilizer in butyl mbbers and as a catalyst in the manufacture of hexadiene. The compound has been shown to be a skin irritant and continuous exposure should be avoided. Toxicological studies indicate that it is nonaccumulative (162). 

Amino-4,6-dinitropheno1 is an important intermediate in the manufacture of colorants, especially mordant dyes. It has also been used as an indicator dye in titrations (yellow with acid, red with alkali) and as a reagent for albumin deterrnination. 

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