Lysine In Position Research Articles

Biolobical activity of corticotrophin peptides with homo-arginine, lysine or ornithine substituted for arginine in position 8.

ABSTRACT The steroidogenic and lipolytic activities of corticotrophin-(1–24)-tetracosapeptide and [Lys17,18]corticotrophin-(1-18)-octadecapeptide amide were compared with those of the corresponding analogues variously substituted in position 8 with homo-arginine, ornithine or lysine. Peptides substituted with homo-arginine showed a surprisingly high degree of biological activity; in all the tests performed, the loss of activity due to the substitution did not exceed a factor of 3 to 10, while peptides substituted with ornithine or lysine in position 8 only showed residual biological activity or none at all, depending on the test system used. The results reported demonstrated that the presence of a guanidino group (arginine or homo-arginine side chain) in position 8 of the ACTH peptide is essential for the preservation of a high level of biological activity; the length of the aliphatic chain carrying the guanidino group is of minor importance.

Distribution of an idiotypic determinant of human light chains in the immunoglobulins of normal individuals.

LIGHT chains of immunoglobulins consist of a variable, N-terminal and a constant, C-terminal, region1. The four chemically and serologically defined variants of the constant region of human light chains of type L are characterized by the exchange of arginine and lysine in position 1912,3 and of serine and glycine in position 1544. These variants are present in all individuals and have been designated isotypic variants5. It has been suggested that they arise from gene duplication followed by mutation3,4. The two variants of the constant region of human light chains of type K are characterized by a single amino-acid substitution in position 1891,6,7. The population is heterogeneous with respect to these variants; they are inherited as Mendelian factors and are an expression of genetic polymorphism. They have been designated allotypic variants5.

Identification of stable intermolecular crosslinks present in reconstituted native collagen fibers

Soluble collagen extracted by 0.2 M cysteamine from rat skin contains 2.5 to 2.7 residues of peptide bound α-aminoadipic semi-aldehyde per α-chain. When reconstituted into fibers and maintained at 37° C these aldehydes become involved in the formation of stable non-reducible crosslinks. Using collagen biosynthetically labeled at the lysine and hydroxylysine positions, these stable crosslinks have been partially identified. Lysinonorleucine and its hydroxyderivative account for 50% of the initial aldehyde residues present on the collagen molecule while two unidentified peaks (post-lysine and post-histidine) account for the other 50%.

Effect of Type of Enrichment and Duration of Incubation on Salmonella Recovery from Meat-and-Bone Meal

Twenty-five meat-and-bone meal samples were enriched with either selenite-cystine or tetrathionate and incubated for 1 and 2 days. Seven were previously found to be positive; of the other 18, 16 were positive for salmonella. The number of somatic serogroups per sample ranged from 1 to 11 with a mean of 3.8. Significantly more (P < 0.01) group C(1) salmonellae were isolated using tetrathionate than selenite, whereas significantly more of groups G, 35, and Difco poly-valent D were isolated from selenite than tetrathionate. Seventy-six percent of the presumptive colonies from Brilliant Green agar showed a positive lysine decarboxylase reaction, and there were no differences between media or times of incubation. Ninety-four per cent of the lysine decarboxylase-positive cultures showed a positive somatic antiserum response; again there were no differences between times or enrichments although there were significantly more total positive serogroups at 2 days than at 1 day from tetrathionate but not from selenite. There were indications that certain serogroups preferred either one or the other enrichment. There were no differences in total positive samples with the two enrichments although neither alone was sufficient to identify all positives. Several lactose-positive salmonellae were recovered.

The reaction of 2,4,6-trinitrobenzene sulfonic acid with pancreatic elastase.

The reaction of elastase with trinitrobenzene sulfonic acid was investigated in the pH range 9–12. Elastase was found to be inactivated by 2,4,6-trinitrobenzene sulfonic acid. The pH dependence of the pseudo first-order inactivation rate constant showed a pK of 10.3 and gave a Hill plot coefficient of 1.15. Trinitrophenol did not inactivate the enzyme. These results indicate that the inactivation is due to the covalent reaction of trinitrobenzene sulfonic acid with a single group in the enzyme. This group is not the N-terminal since the loss of N-terminal valine was considerably slower than the loss of activity at pH 10.5. The inactivation of elastase with 2,4-dinitrofluorobenzene also showed no correlation with the loss of the N-terminal. When the enzyme was exhaustively treated and fully inactivated with trinitrobenzene sulfonic acid at pH 10.5, the N-terminal valine and two out of three lysine residues were trinitrophenylated. No evidence for the loss of histidine was found. One of the tyrosine residues may be trinitrophenylated as judged from the molar extinction of the trinitrophenylated protein, but it has not been possible to isolate a trinitrophenylated tyrosine-containing peptide. The results can be interpreted in one of two ways: (a) trinitrophenylation of a group with a pK of 10.3, not involved in the activity, inactivates because the introduction of the trinitrophenyl residue causes a denaturation of the enzyme; or (b) a group with a pK of 10.3 controls the active conformation of the enzyme. The results do not exclude the possibility that the N-terminal plays an important role in the activity of the enzyme. Below pH 10.5 the reactivity of the N-terminal is low, indicating that it is buried.At pH 9.0 only the ε-amino group of lysine in position 224 reacted with trinitrobenzene sulfonic acid and full activity was retained. The second-order rate constant for the trinitrophenylation of this group was 25 times higher than that of the ε-amino group of the α-N-benzoyllysine.

Structural Analysis of the Glycine-rich, Arginine-rich Histone: III. SEQUENCE OF THE AMINO-TERMINAL HALF OF THE MOLECULE CONTAINING THE MODIFIED LYSINE RESIDUES AND THE TOTAL SEQUENCE

Abstract 1. The amino acid sequence of the amino-terminal portion of the glycine-rich, arginine-rich histone (Residues 1 to 49) has been determined from studies on the tryptic, chymotryptic, and thermolysin peptides. This sequence overlaps with that of the carboxylterminal portion (Residues 50 to 102) defined previously to give the following sequence: acetylSer-Gly-Arg-Gly-Lys-Gly-Gly-Lys-Gly-Leu-Gly-Lys-Gly-Gly-Ala-Lys(Ac)-Arg-His-Arg-Lys(Me)-Val-Leu-ArgAsp-Asn-Ile-Gln-Gly-Ile-Thr-Lys-Pro-Ala-Ile-Arg-Arg-Leu-Ala-Arg-Arg-Gly-Gly-Val-Lys-Arg-Ile-Ser-Gly-Leu-Ile-Tyr-Glu-Glu-Thr-Arg-Gly-Val-Leu-Lys-Val-Phe-Leu-Glu-Asn-Val-Ile-Arg-Asp-Ala-Val-Thr-Tyr-Thr-Glu-His-Ala-Lys-Arg-Lys-Thr-Val-Thr-Ala-Met-Asp-Val-Val-Tyr-Ala-Leu-Lys-Arg-Gln-Gly-Arg-Thr-Leu-Tyr-Gly-Phe-Gly-Gly-COOH. 2. This sequence agrees with that reported recently by DeLange, Fambrough, Smith, and Bonner (J. Biol. Chem., 244, 319 (1969)) except that the arginine residue they placed at position 44 is found in position 40 (and is italicized) in the above sequence. 3. Four clusters of basic residues (underlined) were present in this sequence. The cluster in the amino-terminal portion contained both the modified amino acids e-Nacetyllysine and e-N-methyllysine at positions 16 and 20. The acetyllysine was present in approximately half of the glycine-rich, arginine-rich histone molecules; the methylated lysine position contained mono and dimethyl groups in a ratio of 1:3. This microheterogeneity makes a total of four possible species of the glycine-rich, arginine-rich histone.

Synthesis of α-tritiated L-histidine, L-arginine and L-lysine

Tritium was introduced into the alpha position of histidine, arginine, and lysine by racemization using the azlactone rearrangement in an anhydrous tritiated medium. The monoacetyl derivatives of histidine and arginine were resolved with acylase I; lysine was converted into its α,ϵ-dichloroacetyl derivative and resolved with acylase IA. The α-tritiated l-amino acids recovered from these reactions had the expected optical rotations. The specific activities of l-[α 3H]-histidine·HCl·H 2O, l-[α 3H]-arginine·HCl, and l-[α 3H]-lysine·HCl were 3.40 × 10 9, 4.47 × 10 9, and 1.03 × 10 9 dpm/mmole, respectively. l-[α 3H] Arginine·HCl was converted into l-ornithine·HCl and l-citrulline without change in specific activity. l-Arginine and l-citrulline, when subjected to the action of l-amino acid oxidase, gave α-keto-δ-guanidinovaleric and α-keto-δ-carbamidovaleric acids, which were devoid of any activity. ϵ-Cbzo- l-[α 3H]-lysine was prepared and subjected to the action of l-oxidase. The resulting α-keto-ϵ- N-Cbzo-aminocaproic acid had no activity. l-[α 3H]-histidine·HCl·H 2O was oxidized by nonenzymic means to imidazolelactic acid, cyanomethylimidazole, and imidazoleglyoxylic acid; the compounds retained 100, 8, and 2% of the original activity respectively. β-Imidazolyl-pyruvic acid could not be prepared by the action of venom l-amino acid oxidase. Imidazoleacetic acid prepared with this enzyme in the absence of catalase had 6% of the original l-histidine activity. It is concluded that tritium introduced into arginine and lysine by the azlactone rearrangement is exclusively linked to the α-carbon. For histidine, 92% of the label appeared in the α-position, 6% in the β-hydrogen atoms, and 2% in the imidazole ring. The difficulties in the determination of the tritium activity of histidine and its derivatives by liquid scintillation counting can be overcome by the addition of formaldehyde.

Synthèse de nouveaux analogues de la lysine‐vasopressine: Asp(NH2)4‐lysine‐vasopressine, Ala4‐lysine‐vasopressine, Sér4‐lysine‐vasopressine, Sér5‐lysine‐vasopressine, Val7‐lysine‐vasopressine et (Nϵ‐For‐Lys)8‐vasopressine

AbstractSix new analogues of Lysine‐vasopressin have been synthesized 1 Asp(NH2)4‐lysine‐vasopressin, Ala4‐lysine‐vasopressin, Ser4‐lysine‐vasopressin, Ser5‐lysine‐vaso‐pressin, Val7‐lysine‐vasopressin and (Nϵ‐For‐Lys)8‐vasopressin. All were prepared by the 3 + 6 scheme. The hexapeptides necessary for the synthesis of the former four were prepared by recurrent synthesis, those utilized for the synthesis of the last two, by condensation of two tripeptides. The analogues substituted in position 4 were found to still possess a significant level of activity, whereas those substituted in positions 5 or 7 were almost inactive. Masking of the ϵ‐amino group of lysine in position 8 caused no decrease in the oxytocic activities, but affected, to a different degree, the pressor and the antidiuretic activities.

Decreased or absent ACTH-like activity of blocked synthetic tricosapeptide.

SummarySubstitution of acetyl for hydrogen in the NH2 group of the N-terminal serine, NH2 for OH” in the carboxyl of glutamine in position 5, and formyl for an amino hydrogen of lysine in positions 11, 15, 16, and 21 decreases or eliminates the ACTH-like activity of a synthetic tricosapeptide which duplicates the first 23 amino acids of naturally occurring ACTH.