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PubMed1972

The stereochemical structure of disodium DL-glycerol 3-phosphate hexahydrate, the D isomer of which is an inhibitor of triose phosphate isomerase.

The stereochemistry of dl-glycerol 3-phosphate was studied by X-ray-crystallographic techniques. All the bond lengths and angles are within normally accepted limits except the ester bond, which is one of the largest yet noted, being 0.1637nm. The conformation of the molecule is such that an intramolecular hydrogen bond is formed between the hydroxyl group on the beta-carbon atom and the phosphate group. The crystal, which was grown by alcohol diffusion into an aqueous solution, is held together by sodium co-ordination and a complex system of hydrogen bonds. A table of the observed and calculated structure factors, F(obs.) and F(calc.), has been deposited as Supplementary Publication 50010 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1972) 126, 5.

Carbohydrate Epimerases↗
PubMed1972

The primary structure of aspartate aminotransferase from pig heart muscle. Partial sequences determined by digestion with pepsin and trypsi trypsin.

Peptides obtained by tryptic digestion of carboxymethylated and maleylated aspartate aminotransferase and of the aminoethylated enzyme were isolated and the complete amino acid sequences of most of them were determined. Digestion of the carboxymethylated protein with pepsin produced a complex mixture of peptides that allowed some overlapping of the tryptic peptides (Fig. 4); in addition, peptides were obtained that had not been found in either of the tryptic digests. From these studies about 400 amino acid residues were identified. Experimental details and confirmatory data for the results presented here are given in a supplementary paper that has been deposited as Supplementary Publication 50011 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1972) 126, 5.

Alkylation↗
PubMed1973

The amino acid sequence of cytochrome c from Allium porrum L. (leek).

The amino acid sequence of leek cytochrome c was determined with 0.4mumol of protein. The sequence was deduced solely from a chymotryptic digest. The cytochrome was homologous with other plant cytochromes c of mitochondrial origin. Leek cytochrome c has an N-acetylated ;tail' as compared with mammalian cytochrome c, and two residues of epsilon-N-trimethyl-lysine. Unlike other plant cytochromes c, leek cytochrome c has glutamic acid or glutamine in position 11, leucine in position 20 and alanine in position 51. 4-Hydroxyproline partially substitutes for proline in position 79. Experimental details are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50012, at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5.

Acetylation↗
PubMed1973

The amino acid sequence of cytochrome c from Spinacea oleracea L. (spinach).

The amino acid sequence of spinach (Spinacea oleracea L., var. Monster Viroflay) cytochrome c was determined on 1mumol of protein. The molecule consists of 111 residues and is homologous with other mitochondrial cytochromes c. Experimental details are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50013, at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 5.

Amino Acid Sequence↗
PubMed1973

Amelogenins. Purification and partial characterization of proteins from developing bovine dental enamel.

1. Procedures are described for the purification of amelogenin electrophoretic components and their analysis for homogeneity by polyacrylamide-gel electrophoresis at both acidic and alkaline pH values. 2. Most of these components belonged to two main groups, termed the J group and the C group after their major electrophoretic components. Sodium dodecyl sulphate-polyacrylamide-gel electrophoresis indicated that, within each group, proteins were of similar size, but the C-group proteins were larger than those of the J group. 3. By sedimentation-equilibrium ultracentrifugation and amino acid analysis, the four J-group components were found to be very small proteins (mol. wt. 5500-3000) and, except for one, similar in amino acid composition. The components of the C group were found to be proteins of moderate size (mol. wt. 16800-16100) with very similar amino acid compositions. A third minor amelogenin group of intermediate size was also found, but not further analysed. Details of the results of the ultracentrifuge studies are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50014 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5. 4. Two of the J-group components were similar to amelogenins isolated by other workers. 5. All amelogenins analysed were rich in proline, glutamic acid, histidine and methionine, and contained no half-cystine. Their amino acid compositions, combined with their molecular weights, serve to distinguish the amelogenins from both collagens and keratins.

Amelogenesis↗
PubMed1973

The amino acid sequences of cytochromes c-551 from three species of Pseudomonas.

The amino acid sequences of the cytochromes c-551 from three species of Pseudomonas have been determined. Each resembles the protein from Pseudomonas strain P6009 (now known to be Pseudomonas aeruginosa, not Pseudomonas fluorescens) in containing 82 amino acids in a single peptide chain, with a haem group covalently attached to cysteine residues 12 and 15. In all four sequences 43 residues are identical. Although by bacteriological criteria the organisms are closely related, the differences between pairs of sequences range from 22% to 39%. These values should be compared with the differences in the sequence of mitochondrial cytochrome c between mammals and amphibians (about 18%) or between mammals and insects (about 33%). Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 50015 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 5.

Acetone↗
PubMed1973

Evidence for the amino acid sequence of porcine pancreatic elastase.

The preparation and purification of tryptic peptides from aminoethylated Dip-elastase and [(14)C]carboxymethylated Dip-elastase, and of peptic peptides from native elastase is described. A summary of the results of chemical studies used to elucidate the amino acid sequence of these peptides is presented. Full details are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50016 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 1-20. These results, together with those from previously published papers, are used to establish the complete amino acid sequence of elastase, which is a single polypeptide chain of 240 residues, molecular weight 25900, containing four disulphide bridges.

Amino Acid Sequence↗
PubMed1973

The amino acid sequence of cytochrome c from Nigella damascena L. (love-in-a-mist).

The amino acid sequence of cytochrome c from Nigella damascena L. was determined on 0.2mumol of protein. Peptides from a single chymotryptic digest were analysed by the dansyl-Edman procedure. These peptides were ordered by reference to the sequences of other plant cytochromes c, assuming that the Nigella cytochrome is homologous with the other cytochromes. Many of the Nigella peptides were one or two residues short when compared with the corresponding chymotryptic peptides from other plant cytochromes c. These residues are assumed to have been removed by an endogenous carboxypeptidase, and the identification and placing of these residues is entirely based on homology. These residues are numbered 3, 18, 42, 43, 44, 54, 67, 72, 73, 82 and 105. A number of other positions are almost entirely placed by homology. These are positions which could not be placed definitely by dansyl-Edman analysis or by dansylation after digestion with carboxypeptidase A, and are numbered 14, 15, 16, 39, 40, 85, 86, 87 and 88. Except for residue 15, all residues based entirely, or nearly so, on homology have been previously found invariant in sequences of plant cytochromes c. Experimental details are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50017, at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5.

Amino Acid Sequence↗
PubMed1973

The primary structure of aspartate aminotransferase from pig heart muscle. Partial sequences determined by digestion with thermolysin and elastase.

Peptides produced by thermolytic digestion of aminoethylated aspartate aminotransferase and of the oxidized enzyme were isolated and their amino acid sequences determined. Digestion by elastase of the carboxymethylated enzyme gave peptides representing approximately 40% of the primary structure. Fragments from these digests overlapped with previously reported sequences of peptides obtained by peptic and tryptic digestion (Doonan et al., 1972), giving ten composite peptides containing 395 amino acid residues. The amino acid composition of these composite peptides agrees well with that of the intact enzyme. Confirmatory results for some of the present data have been deposited as Supplementary Publication 50018 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5.

Amino Acid Sequence↗
PubMed1973

Steady-state enzyme kinetics with high-affinity substrates or inhibitors. A statistical treatment of dose-response curves.

A statistical treatment of steady-state enzyme kinetic measurements is described that allows for depletion of free substrate or free inhibitor concentrations owing to significant binding to the enzyme. V(max.), K(m) or K(i), enzyme concentration, the concentration of substrate or inhibitor required for a half-maximal effect and standard errors of these parameters can be calculated from dose-response measurements; the concentration of each component of the system may be estimated also. The statistically best values of the parameters are used to convert dose-response curves into convenient linear forms. The method is applied to dose-response measurements of hydroxyquinoline N-oxide inhibition of bacterial respiration and aminopterin inhibition of dihydrofolate reductase. Two FORTRAN programs for this method have been deposited as Supplementary Publication no. SUP 50019 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1973) 131, 5.

Aminopterin↗
PubMed1973

A hydroxyproline-containing glycopeptide released from the walls of sycamore tissue-culture cells by hydrazinolysis.

Degradation of the sycamore cell wall by hydrazinolysis yielded soluble glycopeptides. The peptide portion of the predominant glycopeptide was shown to be cyclic (4-trans-hydroxy-l-prolyl)-4-trans-hydroxy- l-proline. From this structure and the composition of the major glycopeptide it was deduced that only short oligosaccharides are attached to the hydroxyprolyl residues of the wall glycoprotein. Detailed evidence for the structure of the peptide is given in a supplementary paper that has been deposited as Supplementary Publication SUP 50020, at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5.

Arabinose↗
PubMed1973

The amino acid sequence of cytochrome c' from Alcaligenes sp. N.C.I.B. 11015.

The amino acid sequence of the cytochrome c' from Alcaligenes sp. N.C.I.B. 11015 (Iwasaki's ;Pseudomonas denitrificans') has been determined. This organism is the only non-photosynthetic bacterium in which the protein has been found. The protein consists of a single polypeptide chain of 127 residues, with a single haem covalently attached to two cysteines. Unlike normal cytochromes c, the haem attachment site is very close to the C-terminus. The amino acid sequence around the haem attachment site is very similar to that of Chromatium vinosum D cytochrome c'. Detailed evidence for the amino acid sequence of the protein has been deposited as Supplementary Publication SUP 50022 at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.

Alcaligenes↗
PubMed1973

Relationships between concentration of hepatic intermediary metabolites and induction of the key glycolytic enzymes in vivo.

1. The time-course for the induction of hepatic glucokinase, hexokinase, phosphofructokinase, liver-type and muscle-type pyruvate kinases in reponse to various diets and insulin has been investigated over the first 48h of change in both diabetic and non-diabetic rats. 2. The results are consistent with there being separate regulatory mechanisms for the induction of each of the three key enzymes, that is for glucokinase, phosphofructokinase and liver-type pyruvate kinase. 3. To investigate the possibility that induction of these enzymes is mediated through specific metabolites a full metabolite profile has been determined under conditions identical with those in the induction experiments and the results examined for correlations between metabolite concentrations and enzyme activities. 4. Several such relationships were detected and those between glucokinase activity and the phosphorylation state of the adenine nucleotides and between liver-type pyruvate kinase activity and the concentrations of dihydroxyacetone phosphate and pyruvate are discussed in relation to the concept of inducing metabolites. 5. It is suggested that the induction of glycolytic enzymes by insulin may be secondary to the changes in the concentration of specific hepatic metabolites brought about by the acute effects of the hormone. 6. The details of the metabolite concentrations in the various experimental states have been deposited as Supplementary Publication SUP 50021 at the British Library (Lending Division) (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 5.

Animals↗
PubMed1974

Simulation of the pentose cycle in lactating rat mammary gland.

A computer model representing the pentose cycle, the tricarboxylic acid cycle and glycolysis in slices of lactating rat mammary glands has been constructed. This model is based primarily on the studies, with radioactive chemicals, of Abraham & Chaikoff (1959) [although some of the discrepant data of Katz & Wals (1972) could be accommodated by changing one enzyme activity]. Data obtained by using [1-(14)C]-, [6-(14)C]- and [3,4-(14)C]-glucose were simulated, as well as data obtained by using unlabelled glucose (for which some new experimental data are presented). Much past work on the pentose cycle has been mainly concerned with the division of glucose flow between the pentose cycle and glycolysis, and has relied on the assumption that the system is in steady state (both labelled and unlabelled). This assumption may not apply to lactating rat mammary glands, since the model shows that the percentage flow through the shunt progressively decreased for the first 2h of a 3h experiment, and we were unable to construct a completely steady-state model. The model allows examination of many quantitative features of the system, especially the amount of material passing through key enzymes, some of which appear to be regulated by NADP(+) concentrations as proposed by McLean (1960). Supplementary information for this paper has been deposited as Supplementary Publication SUP 50023 at the British Museum (Lending Division) (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5.

Animals↗
PubMed1974

The tryptic peptides of rabbit muscle triose phosphate isomerase.

1. The peptides obtained by tryptic digestion of S-[(14)C]carboxymethylated rabbit muscle triose phosphate isomerase have been studied. 2. The first step in the fractionation of the tryptic digest was gel filtration on coupled columns of Sephadex G-25 and G-50. Further fractionation was carried out by paper electrophoresis and paper chromatography. 3. The digest contained 26 peptides and three free amino acids. The sizes of the peptides ranged from two to 29 residues. 4. The sequences of the peptides have been determined. 5. The length of the polypeptide chains is about 250 amino acid residues. 6. The variant sequences encountered were due to partial deamidation; this may be one of the reasons for multiple forms of the enzyme. 7. The chicken and rabbit enzymes are compared. 8. Detailed evidence for the sequences of the tryptic peptides has been deposited as Supplementary Publication SUP 50024 at the British Library, Lending Division (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms given in Biochem. J. (1973) 131, 5.

Amino Acid Sequence↗
PubMed1974

Studies on the subunit structure and amino acid sequence of trisoe phosphate isomerase from chicken breast muscle.

1. Triose phosphate isomerase was prepared by chromatography on DEAE-cellulose of an (NH(4))(2)SO(4) fraction of an extract of homogenized chicken breast muscle. The product is homogeneous on gel electrophoresis and is suitable for growing crystals for X-ray work. The specific activity is 10000 units/mg and the value for E(0.1%) (280) is 1.20. 2. Comparison between the sum of the amino acid compositions of the tryptic peptides of the protein and the amino acid composition obtained on total hydrolysis of the protein indicates that the relative subunit mass is about 27000. 3. These data, together with the results of the examination of the amino acid compositions of a number of minor peptides, the number of peptides in the tryptic digest and the complete amino acid sequences of the tryptic peptides (the determination of which is described here), give no indication that the subunits are dissimilar. 4. A tentative amino acid sequence is presented for the protein, in which the ordering of the tryptic peptides is derived by homology with the sequence of the rabbit muscle enzyme (Corran & Waley, 1973). 5. An appendix describes the use that was made of mass spectrometry in the determination of some of the sequences. Mass-spectrometric data have been obtained for 35 residues, that is about 15% of the total sequence of the protein. 6. An extended version of the present paper has been deposited as Supplementary Publication SUP 50025 at the British Library, Lending Division (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.

Amino Acid Sequence↗
PubMed1974

Biospecific affinity chromatography of an adenosine 3':5'-cyclic monophosphate-stimulated protein kinase (protamine kinase from trout testis) by using immobilized adenine nucleotides.

1. Two adenine nucleotides, 8-(6-aminohexyl)aminoadenosine 3':5'-cyclic monophosphate and 8-(6-aminohexyl)amino-AMP, were synthesized. Their structures were established in particular by using mass spectroscopy. 2. Free cyclic AMP and 8-(6-aminohexyl)amino cyclic AMP both stimulate protamine kinase activity at low concentrations, but are inhibitory at concentrations above 0.1mm. AMP is an inhibitor of enzymic activity, whereas neither 8-(6-aminohexyl)amino-AMP nor the earlier synthesized N(6)-(6-aminohexyl)-AMP is inhibitory. 3. The nucleotides were coupled to Sepharose 4B and used for biospecific chromatography of partially purified protamine kinase. Enzyme applied at high buffer concentrations to the cyclic AMP-Sepharose material was retarded and thereby purified tenfold. At low buffer concentrations the enzyme was adsorbed to the affinity material, and was subsequently released by a pulse of the inhibitor AMP, yielding a 50-100-fold purification. Enzyme applied to immobilized 8-(6-aminohexyl)amino-AMP or N(6)-(6-aminohexyl)-AMP was eluted together with the main protein peak in the void volume. 4. Protamine kinase eluted from 8-(6-aminohexyl)amino cyclic AMP-Sepharose was no longer activated by cyclic AMP. Results from sucrose gradient centrifugation suggest that a dissociation of the enzyme took place on the immobilized nucleotide. 5. Further information on the mass spectroscopy has been deposited as Supplementary Publication SUP 50026 at the British Library (Lending Division) (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.

Adenine Nucleotides↗
PubMed1974

The purification and amino acid sequence of cytochrome C-552 from Euglena gracilis.

Cytochrome c-552 from Euglena gracilis was purified and the amino acid sequence determined. The protein is a single peptide chain of 87 residues with the haem prosthetic group bound through two thioether linkages to two cysteine residues near the amino-terminal region. The amino acid sequence shows some similarities to mitochondrial cytochrome c and to two prokaryote c-type cytochromes. The sequence, taken with the known characteristics of cytochrome c-552, indicates that it is an f-type cytochrome. The possible functional and evolutionary significance of these features in common is discussed. Detailed evidence for the amino acid sequence of Euglena cytochrome f has been deposited as Supplementary Publication SUP 50027 at the British Library, Lending Division (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7QB, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5.

Amino Acid Sequence↗