Amino dibasic

Without other alternatives, the carboxyalkyl radicals couple to form dibasic acids HOOC(CH)2 COOH. In addition, the carboxyalkyl radical can be used for other desired radical reactions, eg, hydrogen abstraction, vinyl monomer polymerization, addition of carbon monoxide, etc. The reactions of this radical with chloride and cyanide ions are used to produce amino acids and lactams employed in the manufacture of polyamides, eg, nylon. 

Figure 3. Schematic representation of the PGII, PGI, PGC [13] and PGE proteins from A. niger, indicating the putative processing sites for the signal peptide ( ) and the mono- and dibasic processing site for the propeptide ( ). The position of introns (lA, IB and IC) are indicated ( [) and variation of amino acids number is shown in different parts of protein. The putative N-glycosylation sites are marked ( ).

None of the other reactions so far discussed involve interaction between a pair of charged species. This is but another instance of the electrostatic effect shown by Kirkwood and Westheimer to be responsible for the disparity between the first and second ionization constants of dibasic acids, for the effect of the carboxylate ion on the basicity of an a-amino acid, and for the difference in reactivity of ionic compounds compared with analogous nonionic species in acid- or base-catalyzed reactions. ... 

Fig. n.i. Human duodenal expression variability of peptide and amino acid transporters (our unpublished data). Shaded box indicates 25-75% of expression range, the line within the box marks the median, and error bars indicate 10-90% of expression range. PEPT1, di-, tri-peptide transporter HPT1 (Ll-cadherin) peptide transporter SLC3A1, cystine, dibasic and neutral amino acid transporter y+LATl, cationic amino acid transporter ATBq, neutral... 

Lee, W. S., et al. Cloning and chromosomal localization of a human kidney cDNA involved in cystine, dibasic, and neutral amino acid... 

Wells, R. G. and M. A. Hediger. Cloning of a rat kidney cDNA that stimulates dibasic and neutral amino acid transport and has sequence similarity to glucosidases. Proc. Natl. Acad. Sci. U. S. A 1992, 89, 5596-5600. 

Wells, R. G., et al. The 4F2 antigen heavy chain induces uptake of neutral and dibasic amino adds in Xenopus oocytes. /. Biol. Chem. 1992, 267, 15285-15288. 

The cause is defective transport of dibasic amino acids by the proximal tubule and intestine. The transport defect occurs at the basolateral rather than the luminal membrane. Hyperammonemia reflects a deficiency of intra-mitochondrial ornithine. An effective treatment is oral citrulline supplementation, which corrects the hyperammonemia by allowing replenishment of the mitochondrial pool of ornithine. 

The biochemical defect is a deficiency or mutation of the gene that encodes the common membrane transporter for cystine and the dibasic amino acids. 

The disease is characterized by excessive excretion of cystine and the dibasic amino acids arginine, lysine, and ornithine by the kidneys that may lead to precipitation of some of these compounds in the form of kidney stones. 

For exchange in dibasic compounds, such as aminopyridines, ideally if both equilibrium and kinetic protonations follow H0, a rate profile of the type in Figure 3 should be expected (67JCS(B)1219>. Rate profiles obtained for 4-amino, 4-amino-2,6-dichloro- and 2-amino-5-methyl-pyridine correspond to the portions b-c, c-d and d-e respectively of Figure 3. 

The dibasic side chain at position 7 can be alternatively provided by a substituted amino alkyl pyrrolidine. Preparation of that diamine in chiral form starts with the extension of the ester function in pyrrolidone (46-1) by aldol condensation with ethyl acetate (46-2). Acid hydrolysis of the (3-ketoester leads to the free acid that then decarboxylates to form an acetyl group (46-3). The carbonyl group is next converted to an amine by sequential reaction with hydroxylamine to form the oxime, followed by catalytic hydrogenation. The desired isomer (46-4) is then separated... 

Amino acids with two carboxylic groups or those with two amino groups behave slightly differently in that they are not entirely neutral, but may be acidic or basic. All amino acids therefore have a different isoelectric point (see Table 2.1.1). These differences in polarity form the basis of the separation of amino acids the neutral amino acids are in the middle part of the chromatogram and the dibasic amino acids elute late. In addition, the length of the aliphatic chain of the molecule makes the amino acid less polar, causing later elution (e.g., ornithine, which has five carbon atoms, elutes before its homolog lysine, which has six carbon atoms). 

Diomides. These compds are the dibasic acid derivs of ammonia or amines, and contain two -CONH2 groups. Numerous combinations of diacids, diamines, and amino acids have been interacted. Copolymers contg various proportions of two or more diacids have been prepd (Ref 2). The diamide of carbonic acid is called urea, H2NCONH2. It is a product of animal metabolism and is prepd industrially by reaction of CO2 with excess NH3 at high temp, or by an older method involving the hydrolysis of cyanamide (Ref 5)... 

Barker, P. L. Gendler, P. L. Rapoport, H. Acylation of Dibasic Compounds Containing Amino Amidine and Aminoguanidine Functions, J. Org. Chem. 1981, 46, 2455-2465. 

Dibasic tridentate Schiff bases derived from salicylaldehydes and 2-aminobenzoic acid658 or l-amino-2-mercaptobenzene659 react with aqueous zirconium nitrate to give monomeric complexes of the type [Zr(0H)2(L)(H20)]. IR spectra of these compounds support an ONO-or ONS-tridentate attachment of the (L)2 ligands. 

Cystinuria is a disorder of the proximal tubule s reabsorption of filtered cystine and dibasic amino acids (lysine, ornithine, arginine). 

Cysteine and cystine are relatively insoluble and are toxic in excess.450 Excretion is usually controlled carefully. However, in cystinuria, a disease recognized in the medical literature since 1810,451 there is a greatly increased excretion of cystine and also of the dibasic amino acids.451 452 As a consequence, stones of cystine develop in the kidneys and bladder. Patients may excrete more than 1 g of cystine in 24 h compared to a normal of 0.05 g, as well as excessive amounts of lysine, arginine, and ornithine. The defect can be fatal, but some persons with the condition remain healthy indefinitely. Cystinuria is one of several human diseases with altered membrane transport and faulty reabsorption of materials from kidney tubules or from the small intestine. Substances are taken up on one side of a cell (e.g., at the bottom of the cell in Fig. 1-6) and discharged into the bloodstream from the other side of the cell. In another rare hereditary condition, cystinosis, free cystine accumulates within lyso-somes.453... 

Formulations, Types 6/6 and 6/10 are funned by llie coudeusaliuii of diamines with dibasic organic acids into linear chains containing amide groups. Types 6, 11. and 12 arc sclf-condcnscd amino adds. 

PTA) dibasic amino acids and peptides > 600 Da. PTA soluble N is used as n index of free amino acids Biitikofer et al. (1993), Bican and Spahni (1991), and Gonzalez de Llano et al. (1987, 1991)... 

Deutrolysin had strong hydrolytic activity toward Boc-Arg-Val-Ar-Arg-MCA, with optimal activity at pH 9.0 (Table 8). The kcJKm value of 833 s"1 M"1 was obtained for Boc-Arg-Val-Ar-Arg-MCA. The enzyme hydrolyzed other dibasic-MCA derivatives Pyr-Arg-The-Lys-Arg-MCA, Boc-Leu-Lys-Arg-MCA, Boc-Leu-Arg-Arg-MCA, and Z-Arg-Arg— MCA. However, almost no hydrolysis by the enzyme was found toward mono or certain dibasic peptide-MCAs. The findings indicate that deuterolysin had substrate specificity toward paired dibasic amino acid residues at the P2-P1 positions. 

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