Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: DrugBank:EXPT02079 (lysine)
 58,762 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The properties of the functional groups in a protein can be used as built-in-probes of the structure of the protein. We have developed a general procedure whereby the ionization constant and chemical reactivity of solitary functional groups in proteins may be determined. The method may be applied to the side chain of histidine, tyrosine, lysine, and cysteine, as well as to the amino terminus of the protein. The method, which is an extension of the competitive labeling technique using [3H]- and [14C]1-fluoro-2,4-dinitrobenzene (N2ph-F) in a double-labeling procedure, is rapid and sensitive. Advantage is taken of the fact that after acid hydrolysis of a dinitrophenylated protein, a derivative is obtained which must be derived from a unique position in the protein. The method has been applied to the solitary histidine residue of lysozyme, alpha-lytic protease, and Streptomyces griseus (S.G.) trypsin, as well as to the amino terminus of the latter protein. The following parameters were obtained for reaction with N2ph-F at 20 degrees C in 0.1 N KCl: the histidine of hen egg-white lysozyme, pKa of 6.4 and second-order velocity constant of 0.188 M-1 min-1; the histidine of alpha-lytic protease, pKa of 6.5 and second-order velocity constant of 0.0235 M-1 min-1; the histidine of S.G. trypsin, pKa of 6.5 and second-order velocity constant of 0.0328 M-1 min-1; the valyl amino terminus of S.G. trypsin, pKa of 8.1 and second-order velocity constant of 0.403 M-1 min-1. In addition, the results obtained provide clues as to the microenvironments of these functional groups, and indicate that the proteins studied undergo pH-dependent conformational changes which affect the microenvironment, and hence the chemical reactivity of these groups.
 ...
PMID:A competitive labeling method for the determination of the chemical properties of solitary functional groups in proteins. 0 42

Primary amines react with 2,4-pentanedione at pH 6-9 to form enamines, N-alkyl-4-amino-3-penten-2-ones. The latter compounds readily regenerate the primary amine at low pH or on treatment with hydroxylamine. Guanidine and substituted guanidines react with 2,4-pentanedione to form N-substituted 2-amino-4,6-dimethylpyrimidines at a rate which is lower by at least a factor of 20 than the rate of reaction of 2,4-pentanedione with primary amines. Selective modification of lysine and arginine side chains in proteins can readily be achieved with 2,4-pentanedione. Modification of lysine is favored by reaction at pH 7 or for short reaction times at pH 9. Selective modification of arginine is achieved by reaction with 2,4-pentanedione for long times at pH 9, followed by treatment of the protein with hydroxylamine. The extent of modification of lysine and arginine side chains can readily be measured spectrophotometrically. Modification of lysozyme with 2,4-pentanedione at pH 7 results in modification of 3.8 lysine residues and less than 0.4 arginine residue in 24 hr. Modification of lysozyme with 2,4-pentanedione at pH 9 results in modification of 4 lysine residues and 4.5 arginine residues in 100 hr. Treatment of this modified protein with hydroxylamine regenerated the modified lysine residues but caused no change in the modified arginine residues. One arginine residue seems to be essential for the catalytic activity of the enzyme.
 ...
PMID:Modification of arginine and lysine in proteins with 2,4-pentanedione. 0 43

Autoxidized LA is classified into four groups, LA, LAHPO, SP and FP. Lysozyme is inactivated by these products in the increasing order as follows: FP less than LA less than LAHPO less than SP. The effects of these products on the amino acid composition of lysozyme is examined. All kinds of amino acid residues were not damaged until lysozyme was incubated with LA and LAHPO at 45 degrees C for 100 days. The susceptible amino acid residues attacked by the autoxidized products are tryptophan, lysine and histidine. The specific loss of methionine by SP occurs during acid-hydrolysis. The effect of SP was the strongest among the autoxidized products. FP was almost noneffective. The destructive actions of BP, MA and PA were compared with those of autoxidized products. Effects of these compounds did not resemble those of autoxidized products. It was concluded that tryptophan, lysine and histidine residues were specifically attacked by SP.
 ...
PMID:Lysozyme damage caused by secondary degradation products during the autoxidation process of linoleic acid. 0 40

Reactions of proteins with dehydroalanine or derivatives of dehydroalanine were studied as models for protein crosslinking. Treatment of casein, bovine serum albumin, lysozyme, wool or polylysine with acetamido- and phenylacetamido acrylic acid methyl esters at pH 9-10 converted varying amounts of lysine to lysinoalanine residues. Howver, complete transformation was not achieved. Incomplete reaction is atributed to partial hydrolysis of the esters to the less reactive acrylic acids under the reaction conditions. Similar studies were made of the reactivities of protein SH groups generated by reduction of disulfide bonds by tributylphosphine. The SH groups could be completely alkylated at pH 7.6 in aqueous propanol, as shown by nearly quantitative recovery of lanthionine. Such a procedure might therefore be used to estimate cystine contents of proteins.
 ...
PMID:Reactions of proteins with dehydroalanines. 2 Jul 47

The action of Armillaria mellea protease has been evaluated on a number of polypeptide substrates. It has been shown to split the Pro7-Lys8 bonds in both native and oxidised lysine-vasopressin and the Ser11-Lys12 bond in glucagon. No other splits were detected in these substrates. The enzyme also caused extensive degradation of S-carboxymethyl lysozyme, S-carcoxymethyl pepsinogen and oxidised ribonuclease. A. In each case the only new amino-terminal residue to appear was lysine. A. mellea protease was inhibited by the chelating agents 1,10-phenanthroline, alpha, alpha'-bipyridine and imidazole. The pK1 values (negative log10 of concentration required for 50% inhibition) for these three inhibitors were 3.9, 3.4 and 1.1, respectively. Lysine, S-2-aminoethylcysteine and short chain aliphatic amines also proved to be relatively good inhibitors of A. mellea protease while arginine was a poor inhibitor.
 ...
PMID:Specificity and inhibition studies of Armillaria mellea protease. 2 49

Surface antigens of Actinomyces viscosus T14V were released from cell walls by digestion with lysozyme. These were separated by ion-exchange and gel filtration chromatography into fractions rich in carbohydrate or protein. The former contained a polysaccharide high in 6-deoxytalose, along with a peptide fragment from the cell wall. In the protein-rich fractions, material of high molecular weight was present, which contained some carbohydrate and up to 14.3% nitrogen. Aspartic acid, threonine, glutamic acid, lysine, alanine, and glycine were detected in these fractions, along with smaller amounts of 10 other amino acids. Most of the alanine was present as the L isomer and thus was not from peptidoglycan. Electron microscopy of the high-molecular-weight material revealed long fibrils, 3.5 to 4.5 nm in diameter, which resembled those seen on bacterial cells. V-specific antiserum, prepared by absorbing anti-A. viscosus T14V serum with cell walls of the avirulent strain (A. viscosus T14AV), did not react with the 6-deoxytalose polysaccharide but reacted well with isolated fibrils, and this was not inhibited by 6-deoxytalose.
 ...
PMID:Surface fibrils (fimbriae) of Actinomyces viscosus T14V. 8 16

To examine the effect of amino acid substitutions in lysozyme on the binding of antibodies to lysozyme, we purified lysozyme from the egg whites of California quail and Gambel quail. Tryptic peptides were isolated from digests of the reduced and carboxymethylated lysozymes and subjected to quantitative analysis of their amino acid compositions. The two proteins were identical by this criterion. Each peptide from the California quail lysozyme was then sequenced by quantitative Edman degradation, and the peptides were ordered by homology with other bird lysozymes. California quail lysozyme is most similar in amino acid sequence to bobwhite quail lysozyme, from which it differs by two substitutions: arginine for lysine at position 68 and histidine for glutamine at position 121. California and bobwhite quail lysozymes were antigenically distinct from each other in quantitative microcomplement fixation tests, indicating that substitutions at one or both of these positions can alter the antigenic structure of lysozyme. Yet neither of these positions is among those claimed to account for the precise and entire antigenic structure of lysozyme [Atassi, M. Z., & Lee, C.-L. (1978) Biochem. J. 171, 429--434]. Two possible explanations for this discrepancy are discussed.
 ...
PMID:Amino acid sequence of California quail lysozyme. Effect of evolutionary substitutions on the antigenic structure of lysozyme. 8 64

In order to probe the cause and nature of conformational changes induced by the chemical modification of amino groups in proteins, five acylated derivatives of ovalbumin namely 21% acetylated, 32% succinylated, 90% butyrated 92% succinylated, and 95% acetylated ovalbumins were prepared and their molecular and immunological properties were systematically investigated. As evidenced by the ultraviolet difference spectral, solvent perturbation, gel filtration, and viscosity data, acylation of the amino groups produced a definite conformational change in native ovalbumin whose extent was higher for higher degrees of chemical modification. The solvent pertubation data showed an exposure of 0.5 tryptophan and 3 tyrosine residues in native ovalbumin; the exposure increased to 1 tryptophan and about 5 tyrosine residues in the maximally modified proteins (i.e. 90% butyrated, 92% succinylated, and 95% acetylated ovalbumins). The Stokes radius (2.7 nm) and intrinsic viscosity (3.9 ml/g) of ovalbumin increased, respectively, to about 3.4 nm and 7.7 ml/g upon acylation of its 18 lysine residues; the intrinsic viscosity of 95% acetylated ovalbumin was 7.2 ml/g. The reduced viscosity of ovalbumin (4.2 ml/g) which remained unaltered on raising the pH to pH 11.2, increased to 7.9 ml/g on succinylation of 18 lysine residues. On raising the ionic strength from 0.15 to 1.0, the value decreased from 7.9 to 6.2 ml/g. These observations taken together with the fact that the intrinsic viscosities of 92% succinylated and 90% butyrated ovalbumins are identical, argue against the presently prevalent proposal that electrostatic effects alone are responsible for the disruption of native protein conformation during chemical modification. The immunological activity of ovalbumin towards rabbit anti-ovalbumin expectedly decreased with acylation of its amino groups but the three maximally modified ovalbumins retained 40% immunological activity. This taken along with the spectral and viscosity data showed substantial native structure (format) in the three maximally acylated derivatives. The rabbit antiserum against 95% acetylated ovalbumin did not cross-react with acetylated lysozyme and reacted poorly with the native and 92% succinylated ovalbumins suggesting that the antigenic make-up of the three maximally modified ovalbumins is different.
 ...
PMID:Changes in conformation and immunological activity of ovalbumin during its modification with different acid anhydrides. 10 Dec 49

The chemical structure of the adjuvant active fraction of mycobacterial cell walls has been investigated. It had been shown previously that soluble peptidoglycan fragments obtained from cell walls of Mycobacteria by lysozyme digestion or by other treatments act as adjuvants for increasing both humoral and cellular immunity. We then found that even the monomer subunit of the peptidoglycan of Mycobacteria (i.e. a disaccharide-tetrapeptide) is adjuvant active; then, similar compounds from other strains of bacteria were tested; the monomeric subunits of meso-diaminopimelic acid as well as L-lysine containing peptidoglycans were found to be adjuvant active. The smallest active compound studied so far is N-acetyl-muramyl-L-alanyl-D-isoglutamine synthesized for us by SINAY et al. (1975).
 ...
PMID:Peptidoglycan adjuvants: minimal structure required for activity. 12 66

The substrate specificity of the catalytic subunit of rabbit skeletal muscle 3': 5'-cyclic AMP-dependent protein kinase (EC 2.7.1.37; ATP: protein phosphotransferase) has been studied using the synthetic peptide Arg-Gly-Tyr-Ser-Leu-Gly corresponding to the sequence around serine 24, a phosphorylation site in reduced, carboxymethylated, maleylated (RCMM) chicken egg white lysozyme. This peptide served as a substrate for the enzyme and exhibited a 6-fold higher Vmax and a 100-fold higher Km than RCMM-lysozyme. Replacement of the arginine with glycine, histidine, or lysine resulted in a dramatic reduction in the Vmax. These results support the concept that arginine is an important residue in determining the substrate specificity of the protein kinase, predominantly influencing the Vmax of the phosphorylation reaction. Two synthetic peptides in which serine was replaced by an alanine acted as competitive inhibitors of phosphorylation of the synthetic peptide substrate and RCMM-lysozyme.
 ...
PMID:Synthetic hexapeptide substrates and inhibitors of 3':5'-cyclic AMP-dependent protein kinase. 17 70


1 2 3 4 5 6 7 8 9 10 Next >>