Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: CAS:56-41-7 (alanine)
 70,945 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The splanchnic-hepatic metabolism of glucose, lactate, pyruvate, alanine, glycerol, non-esterified fatty acids (NEFA), ketone bodies and oxygen were investigated in five normal men and six juvenile diabetic subjects at rest and during exercise after an overnight fast. A linear relationship was found between load (arterial concentration multiplied by hepatic blood flow) and splanchnic-hepatic uptake of lactate, pyruvate, glycerol and NEFA. The uptake of alanine was highly sensitive to load, but was also regulated by the concentration of hepatic venous glucagon. The uptake of pyruvate was high in exercising diabetic subjects, who had a high lactate/pyruvate concentration ratio in hepatic venous blood. The rate of uptake of the total measured gluconeogenic precursors was significantly higher in the diabetic group at a given load. The rate of ketogenesis was linearly related to the NEFA load in both groups; however, the rate of ketogenesis was twofold at a given load in the diabetic group. The highest rates of ketogenesis were found coincident with the highest concentrations of glucagon in hepatic venous blood. The observed antiketogenic effect of exercise was due to a decreased load of NEFA, mainly caused by a decrease in the hepatic blood flow.
Clin Sci Mol Med 1977 Nov
PMID:Regulation of gluconeogenesis and ketogenesis during rest and exercise in diabetic subjects and normal men. 20 21

Among temperature resistant revertants of a temperature sensitive E. Coli alanyl-tRNA synthetase mutant a strain was found which contains an alanyl-tRNA synthetase with an additional mutation in the structural gene of the enzyme. This mutant enzyme has a 9 or 38 fold decreased Km value for alanine compared to that of the thermolabile parental enzyme or to wild-type enzyme, respectively. The alaS gene maps just counterclockwise from recA on the E. coli map (94% cotransduction frequency). It appears that the enzyme's increased affinity for alanine is the mechanism of suppressing the temperature sensitive character of the cell. In addition, some cold-sensitive temperature resistant revertants were found, where the cold-sensitive character mapped near strA. Presumably they are due to changes in ribosomal proteins as characterized by Ruffler et al. (1974).
Mol Gen Genet 1977 Nov 14
PMID:Suppression of a defective alanyl-tRNA synthetase in Escherichia coli: a compensatory mutation to high alanine affinity. 34 Sep 3

The amino-acid compositions of the mitochondrial ribosomal subunits of Saccharomyces cerevisiae have been determined and compared to those of cytoplasmic ribosomal subunits. For the large subunits, the mitochondrial and cytoplasmic ribosomes showed major differences in the proportions of arginine, alanine and methionine. For the small subunits, arginine, aspartic acid, alanine, valine and methionine showed marked differences. We have compared these amino-acid compositions with those already published of bacterial and eukaryotic ribosomes by a statistical method of data analysis. It appeared clearly that the yeast mitoribosomes are more distant from bacterial ribosomes than from eukaryotic cytoribosomes.
Mol Gen Genet 1979 Mar 27
PMID:Comparison of amino acid compositions of mitochondrial and cytoplasmic ribosomal proteins of Saccharomyces cerevisiae. 37 18

Aminoacyl tRNA synthetases discriminate between tRNA species by a highly specific mechanism. Physical and chemical studies indicate that the synthetases bind along and around the inside of the three-dimensional L-shaped tRNA structure. Studies of mutant tRNAs that affect synthetase interaction tend to confirm this conclusion. However, in contrast to proteins that recognize a specific block of contiguous nucleotide units (e.g., repressors, restriction enzymes, etc.), synthetases appear to interact with spatially disperse elements of the structure. Available evidence suggests that tRNA binding clefts on various synthetases may be roughly similar, with specificity being achieved by the choice of amino acid residues in a few critical positions in the tRNA binding clefts. With this idea in mind, it should be possible to introduce amino acid substitutions into the binding clefts and thereby change tRNA recognition specificity. This has been attempted (by genetic manipulations) and a mutant alanine tRNA synthetase with altered tRNA recognition has been isolated. This enzyme can attach alanine to isoleucine specific tRNA. When presented with valine specific tRNA, a tRNA similar in some structural features to the isoleucine specific tRNA, or with the structurally quite different tyrosine specific tRNA, no significant aminoacylation occurs. Thus, a precise specificity alteration can occur through mutation; this result supports the idea of similarities in synthetase binding clefts, with specificity being achieved by the positioning of amino acids at critical positions in these clefts. Finally, further data have been obtained on the issue of possible transient covalent bond formation between synthetases and tRNAs, as a critical part of the interaction.
Mol Cell Biochem 1979 May 06
PMID:Recent results on how aminoacyl transfer RNA synthetases recognize specific transfer RNAs. 38 92

The current status of the purification and characterization of human angiotensinogen is reviewed. One problem encountered in the past has been the copurification of a protein with similar porperties. This protein has tentatively been designated alanine-protein. An efficient separation of angiotensinogen and alanine-protein was obtained on a zinc chelate column. Alanine-protein has been purified and its amino acid and carbohydrate composition determined. The COOH-terminal amino acid and the NH2-terminal amino acid were determined to be serine and alanine, respectively. Alanine-protein exhibited multiple forms on isoelectric focusing.
Mol Cell Biochem 1979 Sep 28
PMID:Human plasma angiotensinogen: a review of purification procedures. 39 Mar 63

A mutation affecting alanine-alpha-ketoisovalerate transaminase activity has been shown to be cotransducible with ilv gene cluster. The transaminase deficiency results in conditional isoleucine auxotrophy in the presence of alanine.
Mol Gen Genet 1979 Oct 02
PMID:Identification of a mutation affecting an alanine-alpha-ketoisovalerate transaminase activity in Escherichia coli K-12. 39 46

The effect of the exchangeable cation on the condensation of glycine and alanine was investigated using a series of homoinic bentonites. A cycling procedure of drying, warming and wetting was employed. Peptide bond formation was observed, and the effectiveness of metal ions to catalyze the condensation was Cu2+ greater than Ni2+ approximately Zn2+ greater than Na+. Glycine showed 6% of the monomer incorporated into oligomers with the largest detected being the pentamer. Alanine showed less peptide bond formation (a maximum of 2%) and only the dimer was observed.
J Mol Evol 1979 Nov
PMID:The role of metal ions in chemical evolution: polymerization of alanine and glycine in a cation-exchanged clay environment. 51 39

Complexes of DNA with polypeptides composed of Lys, Ala, and Gly in both a sequential order, poly(L-lysine-L-alanine-glycine), and a statistical distribution, poly(L-lysine36-L-alanine28-glycine), were prepared using gradient dialysis. These polypeptide-DNA complexes were studied using ultraviolet absorption (UV) and circular dichroism (CD) to probe the conformation, binding, and melting behavior of DNA in the complex. Complexes with the sequential polypeptide showed no structural change in the DNA; however, the complexes with the random polypeptide yield CD spectra similar to phi DNA [Maniatis, T., Venable, Jr., J.S., and Lerman, L.S. (1974), J. Mol. Biol. 84, 37]. A second sequential polypeptide, poly(L-Lys-L-Ala-L-Pro)n, -DNA complex was also studied. It was found to exhibit pronounced structural changes as a function of ionic strength and poly-peptide-DNA ratio, more similar to the random sequence that the ordered sequence of the Lys, Ala, Gly polymer. Thus the importance of the composition and amino acid sequence in polypeptides which bind to DNA, even in such simple systems, is demonstrated. Evidence from thermal denaturation, employing simultaneous monitoring of CD and UV changes, supports a model in which specific polypeptides cause condensation of the DNA in the complex into an asymmetric tertiary structure. The relevance of these model systems to chromatin is discussed.
 ...
PMID:Interaction of DNA with poly(L-Lys-L-Ala-Gly) and poly(L-Lys-L-Ala-L-Pro). Circular dichroism and thermal denaturation studies. 55 95

Using quantitative gel filtration techniques partition coefficients, Kp-values, have been determined between aqueous cationic micellar hexadecyltrimethylammonium bromide, CTAB, and several biomonomer. Kp-values for 5'-adenylic acid, 5'-cytidylic acid, 5'-guanylic acid, 5'-uridylic acid and 5'-thymidylic acid are 1,400 +/- 150. Nucleotides bind to CTAB micelles effectively, but nonselectively. Conversely, the binding of tRNAs to micellar CTAB is selective. Kp-values for glutamic acid II, tyrosine and phenylalanine tRNAs (in 1.0MNaCl) are 520, 3,100 and 5,600, respectively. Kp-values for the binding of alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, phenylalanine, serine, threonine and tryptophan to micellar CTAB are less than 8. Conversion of unitless Kp-values for the binding of amino acids, nucleotides and nucleosides to both anionic and cationic micelles, to K (in 1/g) values allows the comparison of clays and micelles as prebiotic concentrating media. Using correlations between surface densities of the biomonomers and their binding constants, it is shown that aqueous micelles (at pH = 8) are a better concentrating media than are clays.
J Mol Evol 1977 Dec 29
PMID:Partitioning of amino acids and nucleotides between water and micellar hexadecyltrimethylammonium halides. The prebiotic significance of cationic surfaces. 59 74

The conformation of some regular polypeptides: (Lys-Ala)50, (Lys-Ala2)37, (Lys-Ala2)26, (Lys-Ala3)18, (Lys3-Pro)29, (Orn3-Gly)28 was studied by means of CD. The complexes of these polypeptides with DNA were obtained by the methods of jump-dilution of a two-components mixture from 2 M NaCl to 0.05 M NaCl. The extent of DNA covering by the polypeptides was compared using binding isoterms of ethidium on DNA and DNA-polypeptide complex. The length, L, which polypeptides cover on DNA was estimated by means of energy transfer between the dyes absorbed on the complexes. The CD spectra of the complexes revealed a high sensitivity to changes of the environmental conditions. Small variations in the temperature and ionic strength produces marked changes in the CD spectra of the complexes. It was suggested that observed CD changes are due to both the structural relaxation of the complexes and the existence of liquid-crystal domains in solution.
Mol Biol (Mosk)
PMID:[Structure of DNA complexes with regular polypeptides]. 65 74


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