Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nucleotide sequence of the bovine alpha-lactalbumin gene, whose organization is very similar to that of its rat counterpart, was deduced from the analysis of 2 lambda clones isolated from a HindIII genomic bank. The 3090 sequenced nucleotides comprise 738 bp upstream from the transcription unit (approximately 2 kb) which contains 4 exons of 160, 159, 76 and 330 bp separated by 3 introns of 321, 473 and 504 bp. Comparison with the rat alpha-lactalbumin gene shows similar percentages of homology between the 4 cognate exons. Since only the first three exons are homologous to the corresponding exons of the lysozyme gene, it is suggested that the 4th exons of alpha-lactalbumin and lysozyme genes have different origins. The bovine alpha-lactalbumin mRNA is 725 nucleotides long, excluding the poly(A) tail. The reading frame and the flanking 5' and 3' untranslated regions contain 429, 27 and 269 nucleotides, respectively. The derived amino acid sequence differs at 10 positions from that determined directly on mature alpha-lactalbumin.
 ...
PMID:Complete nucleotide sequence of bovine alpha-lactalbumin gene: comparison with its rat counterpart. 312 Jul 95

It was found that pigeon lysozyme binds one calcium ion, as does equine lysozyme. The protein was eluted with equimolar calcium ions from a Bio-Gel P-60 column. The binding constants of equine and pigeon lysozymes were determined to be 2 x 10(6) and 1.6 x 10(7) M-1, respectively, in 0.1 M KCl at pH 7.1 and 20 degrees C. During evolution the gene of calcium-binding lysozyme is deduced to be separated from that of non-calcium-binding lysozyme by gene duplication before splitting of avian and mammalian lineages, from their amino-acid sequences. It is assumed that the alpha-lactalbumin might have evolved from calcium-binding lysozyme.
 ...
PMID:Calcium-binding lysozymes. 321 51

Two Raman bands at 880 and 1360 cm-1 of tryptophan (Trp) side chains have been found useful in structural studies of the side chains in proteins. The frequency of the 880-cm-1 band reflects the strength of H bonding at the N1H site of the indole ring: the lower the frequency is, the stronger the H bonding is. The intensity of the 1360-cm-1 band, on the other hand, is a marker of the hydrophobicity of the environment of the indole ring: particularly strong in hydrophobic environments. It is also demonstrated that a combination of stepwise deuteration of the tryptophan side chains and difference spectrum techniques is useful to observe these marker bands due to each side chain separately. The states of six tryptophans in lysozyme revealed by this Raman spectroscopic method in solution are compared with those by X-ray diffraction in crystal. The Raman data on the outer four Trp's are consistent with the X-ray structure, whereas significant differences between solution and crystal are suggested for the strength of H bonding of the most and second most buried Trp's. Characterization of four Trp's in alpha-lactalbumin shows that the two outer Trp's are moderately H bonded to solvent water and closely surrounded by aliphatic side chains while the inner two are not H bonded nor closely surrounded by aliphatic side chains.
 ...
PMID:Characterization of individual tryptophan side chains in proteins using Raman spectroscopy and hydrogen-deuterium exchange kinetics. 334 46

Protein patterns of skim milk and fat globule phases were relatively unchanging throughout 9 months lactation, the only notable differences being a rise in lysozyme and a decline up to 6 months with increase thereafter in lactoferrin. Profound changes in protein patterns of the breast secretion were observed during the first week postpartum. True colostrum, in which peptides of sIgA dominate the protein patterns, exists for at most the 2 initial days of secretion. Proteins of mature milk are not coordinated to appear in the colostral secretion simultaneously. A band corresponding to alpha-lactalbumin is present from the initial secretion; that for beta-casein emerges approximately 2 days layer.
 ...
PMID:Gel electrophoretic analysis of proteins in human milk and colostrum. 358 91

The crystal structure of baboon alpha-lactalbumin has been determined at 6 A and at 4.5 A (0.6 nm and 0.45 nm) resolution by the method of isomorphous replacement. The principal derivative was prepared by reducing a disulphide bridge in the crystals and inserting a mercury atom. Detailed comparison of the electron-density maps with corresponding maps of hen egg-white lysozyme shows that they are closely similar, with correlation coefficients of 0.57 and 0.44 at 6 A and 4.5 A resolution respectively. This result, in accordance with earlier predictions based upon comparisons of amino-acid sequences, provides further evidence that class C lysozymes and alpha-lactalbumins are homologous proteins and it is in keeping with the hypothesis that the alpha-lactalbumins evolved from a lysozyme precursor.
 ...
PMID:Crystallographic analysis of the three-dimensional structure of baboon alpha-lactalbumin at low resolution. Homology with lysozyme. 359 55

The radioallergosorbent test (RAST) and RAST inhibition test were used to examine cross-allergenicity amongst the major hen's egg-white and egg-yolk proteins. Using ovalbumin as a reference allergen to compare cross-reactivity, it was apparent that the proteins conalbumin, ovomucoid and lysozyme substantially inhibited binding to ovalbumin discs of IgE in the sera of patients clinically hypersensitive to egg. The converse situation with conalbumin, ovomucoid and lysozyme on the discs and ovalbumin as the inhibitor also resulted in significantly decreased levels of IgE binding to the proteins on the discs. It was also demonstrated that cross-reactions occurred between ovalbumin and the yolk protein, apovitellenin I. Cross-reaction was also observed surprisingly when egg lysozyme was on the disc and the milk protein allergen alpha-lactalbumin was used as the inhibitor. The demonstration of cross-reaction between all of these proteins may signify that there are a number of common allergenic determinants on these egg proteins, thus providing a molecular basis for the phenomenon of cross-reactivity.
 ...
PMID:Allergenic cross-reactivity of egg-white and egg-yolk proteins. An in vitro study. 365 6

Hydropathic profiles obtained from the amino acid sequences of 8 alpha-lactalbumins were averaged and compared to the average profile deduced from the primary structure of 21 type c lysozymes. This analysis was performed in order to detect differences between both types of molecules, since it could explain their different functional properties. The application of the method herein described reveals the existence of very significative differences (P less than 0.001) between the amino acid residues located at positions 31-32, 34-35, 37-45, 47-48, 80-85 and 108-113 of alpha-lactalbumins and their homologous in type c lysozymes. These differences are in agreement with the chemical data about the interaction sites of both galactosyltransferase and calcium ions with alpha-lactalbumin, which are not required for the lysozyme function.
 ...
PMID:Relationship between hydropathic variability and functional properties of alpha-lactalbumins and type c lysozymes. 365 26

It was found that equine lysozyme binds one Ca2+. It was eluted with equimolar Ca2+ from a Bio-Gel P-4 column. Human lysozyme did not behave similarly. Equine lysozyme is concluded to be a calcium metallo-protein like alpha-lactalbumin, which is a homologue of hen egg white lysozyme.
 ...
PMID:The calcium-binding property of equine lysozyme. 366 56

The major whey proteins of the milks of the dolphin, manatee, and beagle were purified by gel filtration and ion exchange chromatography and characterized and identified by molecular weight determination, amino acid analysis, N-terminal sequencing, and activity measurements. The major whey protein components from all three species were found to be monomeric beta-lactoglobulins. These proteins were all active in binding retinol. Dolphin milk contained two beta-lactoglobulins (designated 1 and 2) which showed a slight difference in molecular weight and considerably divergent N-terminal sequences, whereas the other milks only contained a single form of beta-lactoglobulin. alpha-Lactalbumins were purified from dolphin and dog milks and were active in promoting lactose synthesis by bovine galactosyltransferase. The dolphin protein had an N-terminal sequence more similar to ruminant alpha-lactalbumins than to those known from other species. Although alpha-lactalbumin activity has been detected in manatee milk at low levels, the corresponding protein was not isolated. In addition, dog milk was found to contain high levels of lysozyme (greater than 1.0 mg/ml), which were identified by activity and sequencing. The functional and evolutionary implications of these results are discussed.
 ...
PMID:Purification and characterization of the major whey proteins from the milks of the bottlenose dolphin (Tursiops truncatus), the Florida manatee (Trichechus manatus latirostris), and the beagle (Canis familiaris). 370 36

Comparative studies of the unfolding equilibria of two homologous proteins, bovine alpha-lactalbumin and hen lysozyme, induced by treatment with guanidine hydrochloride have been made by analysis of the peptide and the aromatic circular dichroism spectra. The effect of the specific binding of Ca2+ ion by the former protein was taken into account in interpreting the unfolding equilibria of the protein. Proton nuclear magnetic resonance spectra of alpha-lactalbumin were also measured for the purpose of characterizing an intermediate structural state of the protein. In previous studies, alpha-lactalbumin was shown to be an exceptional protein whose equilibrium unfolding does not obey the two-state model of unfolding, although lysozyme is known to follow the two-state unfolding mechanism. The present results show that the apparent unfolding behavior of alpha-lactalbumin depends on Ca2+ concentration. At a low concentration of Ca2+, alpha-lactalbumin unfolds with a stable intermediate that has unfolded tertiary structure, as evidenced by the featureless nuclear magnetic resonance and aromatic circular dichroism spectra, but has folded secondary structure as evidenced by the peptide circular dichroism spectra. However, in the presence of a sufficiently high concentration of Ca2+, the unfolding transition of alpha-lactalbumin resembles that of lysozyme. The transition occurs between the two states, the native and the fully unfolded states, and the cooperativity of the unfolding is essentially the same as that of lysozyme. Such a change in the apparent unfolding behavior evidently results from an increase in the stability of the native state relative to that of the intermediate induced by the specific Ca2+ binding to native alpha-lactalbumin. The results are useful for understanding the relationship between the protein stability and the apparent unfolding behavior.
 ...
PMID:Ca2+-induced alteration in the unfolding behavior of alpha-lactalbumin. 371 Oct 60


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