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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Sephadex G-200 gel filtration fractions C1 to C6 of the water-soluble lens proteins of Calotes versicolor have been characterized by polyacrylamide gel electrophoresis (PAGE), 7 M urea PAGE, SDS PAGE, and immunological tests. C1 fraction, an alpha-crystallin which cross-reacts with chick alpha, has very low amount of B chains. It shows two bands in SDS PAGE, one strong and another weak. C2 and C3 fractions, both of which partially cross-react with chick beta-crystallins, are largely similar but not identical. C2 in SDS PAGE produces a faint band with a molecular weight of 54,500, which suggests that C2 may either contain a small amount of delta-crystallin in addition to beta H crystallin or that Calotes beta H has a high molecular weight subunit like human beta H; however, in immunological tests no material cross-reacting with chick delta was seen. C4 and C5 are low molecular weight, monomeric, and basic proteins which in all probability are not gamma-crystallins.
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PMID:Studies on the water-soluble lens proteins of the lizard, Calotes versicolor. II. Electrophoretic and immunological characterization. 618 21

Large quantities of calf gamma-crystallin can be prepared by a single and rapid salting-out procedure. The final product is indistinguishable from the gamma-crystallin fraction obtained after gel filtration of a 15000 g lens protein supernatant over Sephadex G 200. Further fractionation is achieved by the mild procedure of chromatofocusing yielding six to eight subfractions. The latter have been characterized by polyacrylamide gel electrophoresis (PAGE) in 6 M-urea, SDS-gel electrophoresis, partial digestion with Staphylococcus aureus protease and amino acid analysis.
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PMID:Large-scale preparation of gamma-crystallin and fractionation by chromatofocusing. 634 4

A lens serine proteinase with trypsin-like specificity has been purified to homogeneity. This is one of two serine proteinases associated with the alpha-crystallin fraction from bovine lens. The purification was accomplished by a combination of isoelectric precipitation, activation to release the proteinase, gel-filtration and affinity chromatography. The purified proteinase showed a single protein band of 25 000 daltons on SDS-PAGE. A single protein band was also seen on non-denaturing gels which correlated with the location of the proteinase activity. The proteinase had a pH optimum between 7.2 and 8.2, was stable between pH 5.8 and 8.6 but was unstable above 40 degrees C upon heating. The enzyme lacked any requirement for metal ions and hydrolyzed arginine, lysine and asparagine substrates. alpha-Crystallin, and especially the B-chain of alpha-crystalline, was rapidly hydrolyzed by the proteinase compared to other lens crystallins. Metallo- and cysteine-proteinase inhibitors had no effect upon the enzyme activity whereas three different serine-proteinase inhibitors completely abolished all activity. A number of protein and peptide trypsin inhibitors also completely inhibited the lens 25K serine proteinase.
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PMID:Isolation and characterization of a 25K serine proteinase from bovine lens cortex. 636 10

An inhibitor of trypsin-like proteinases was isolated from the water-soluble proteins of bovine lens cortex. The inhibitor was purified by four simple procedures: the separation of the inhibitor fraction by Agarose A-1.5 m gel filtration, extraction with 2.5% TCA at 70 degrees C, ammonium sulfate precipitation of the TCA-soluble proteins and a final separation by gel filtration chromatography. This preparation was found to be homogeneous by SDS-PAGE with an approximate subunit molecular weight of 5500 daltons. Gel filtration separated the ammonium sulfate precipitate into an inactive high-molecular-weight peak which eluted in the void volume, and two peaks of approximately 40 000 daltons and 10 000 daltons. Both low-molecular-weight peaks gave a single 5500 dalton band on SDS-PAGE, but only the 40 000 dalton peak was active when concentrated and assayed with bovine trypsin. These data suggest that the inhibitor is present in multimeric forms in solution, but only the octamer appears to be active. Antibodies prepared against the purified inhibitor showed a single precipitin line, while no reaction was seen with an alpha-crystallin antiserum. Upon storage in solution all of the inhibitor became converted into a high-molecular-weight form which was completely inactive. SDS-PAGE dissociated the inhibitor aggregate into a major 44 000 dalton band along with several minor bands. Amino acid analysis showed that the purified inhibitor contains a very high content of hydrophobic residues. The lens inhibitor was effective in reducing the activity of trypsin, but complete inhibition was not seen even at high inhibitor levels. A rapid and complete inhibition was observed, however, with two endogenous trypsin-like proteinases isolated from the alpha-crystallin region.
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PMID:Purification and properties of a protein from bovine lens which inhibits trypsin and two endogenous lens proteinases. 640 63

Aldose reductase (alditol:NADP oxidoreductase EC .1.1.1.21), an enzyme in the sorbitol pathway which has been implicated in the pathogenesis of diabetic complications, has been purified from rat lens (RLAR) by affinity chromatography with Amicon Matrex Gel Orange A and its properties have been compared to those of purified human placental aldose reductase (HPAR). The RLAR appears to be closely associated with alpha- and beta-crystallin and has a higher affinity for the dye Matrex column than HPAR. The purified enzyme, obtained upon elution from the column, appears as a closely-spaced doublet of approximately 38 K MW on SDS-PAGE which does not immunologically cross-react with antibodies raised against the single 38 K MW HPAR. Antibodies raised against RLAR however do cross-react with HPAR. Kinetic studies indicated both enzymes to have a greater apparent affinity for aliphatic and aromatic aldehydes than for aldose sugars. Compared to DL-glyceraldehyde, RLAR displayed an 80-fold greater affinity for p-nitrobenzaldehyde and a 1000-fold decreased affinity for D-glucose while HPAR displayed a 15-fold greater affinity for p-nitrobenzaldehyde and 600-fold less affinity for D-glucose. Both enzymes displayed only trace activity with 200 mM L-gulonic acid.
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PMID:Rat lens aldose reductase: rapid purification and comparison with human placental aldose reductase. 642 98

The lens crystallins were analyzed in normal dogs and Miniature offSchnauzer dogs with congenital cataract formation. There was an increase in the relative proportions of alpha and beta L-crystallin and a decrease in the beta H and gamma-crystallin with increasing age in the noncataractous lens. These trends were advanced in the age-matched cataractous lenses. "Advanced aging" trends were also noted in various polypeptide components of beta-crystallin. Specifically, the appearance of a 29K band as well as a reversal of the 26K to 27.6K ratio occurred at an earlier age in the cataractous lens than in the clear lens. Three subunits of approximately 19K, 20K, and 21.5K were present on SDS-PAGE for alpha-crystallin from the cataractous lens as opposed to only two of 19K and 21.5K from the clear lens. However, if the protein was not heated following resolubilization in buffer containing 2% SDS and 5% 2-mercaptoethanol, only two subunits of 20K and 21.5K were evident in both clear and cataractous lenses. The electrophoretic behavior observed for both alpha and gamma-crystallins did not appear to be age related.
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PMID:Isolation and characterization of the crystallins of the normal and cataractous canine lens. 646 67

Lenses from 19-day chick embryos are fractionated by a double punch method to obtain the epithelium-annular pad complex (EP), outer fibres (OF), middle fibres (MF) and central fibres (CF). Water-soluble crystallins are characterized by SDS PAGE, isoelectric focusing (IEF) and two-dimensional IEF-SDS PAGE. Crystallins are also characterized by immunoelectrophoresis (IE), rocket IE, IEF-immunoblotting, and quantified by two-dimensional antigen-antibody crossed electrophoresis using antibodies to total 19-day embryonic as well as adult crystallins. In the adult lens, alpha-, beta- and delta-crystallins are 19%, 67% and 14%, respectively, while these are present at concentrations of 9%, 27% and 64%, respectively, in 19-day embryonic lens. In absolute amounts, delta-crystallin increases only by 1.23-fold between 19-day embryonic age and 6 months post-hatching, while total lens protein increases 12.5-fold. The predominance of delta-crystallin in central fibres, located along the optical axis, suggests that this protein is of embryonic origin. delta-Crystallin from fibres is electrofocused as 12 distinct molecular classes (pI 5.2-5.42) which react against anti-delta-crystallin on an immunoblot. Of these, the three most anodal species are not detected in EP. Fibres contain 50 000, 48 000 and 45 000 dalton delta-crystallin subunits while only 50 000 and 48 000 dalton subunits are present in EP.
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PMID:Immunochemical characterization and quantitative distribution of crystallins in the epithelium and differentiating fibre cell populations of chick embryonic lens. 649 59

The nucleotide sequence of a full length cDNA of delta-crystallin mRNA from chicken lens has been determined using a delta-crystallin cDNA clone (pB delta 11), which represents the mRNA sequence of 1530 nucleotides from the poly(A) junction but does not contain the 5'-terminal sequence of 44 nucleotides of the mRNA. The 5'-terminal sequence of the mRNA, absent in the cDNA clone, has been determined with a stretch of cDNA sequence by the primer extension procedure. The amino acid sequence deduced from the nucleotide sequence is consistent with the amino acid sequences of several tryptic peptides, the total amino acid composition, and the mol. wt. of delta-crystallin estimated by SDS-polyacrylamide gel electrophoresis. The computer-assisted analysis predicts high alpha-helical content throughout the polypeptide. Sequence analyses have revealed that gene 1 encodes the mRNA from which the cDNA clone was derived.
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PMID:The nucleotide sequence of a complete chicken delta-crystallin cDNA. 654 70

SDS-PAGE revealed a major Mr 48 000 polypeptide of pI around 8 in the water-soluble fraction of lamprey lenses. It occurs as a monomeric protein, and its amino acid composition and tryptic peptides show no resemblances to alpha-, beta-, gamma- or delta-crystallin. Immunoblotting with antiserum against the 48-kDa protein revealed an immunologically related polypeptide of similar Mr in reptiles, several birds and a fish, but showed no cross-reactivity with any other water-soluble lens component. The 48-kDa protein is not detected in many birds and fishes, and in the investigated mammals and amphibians.
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PMID:Lamprey 48-kDa lens protein represents a novel class of crystallins. 662 73

Calf lens nuclear alpha-crystallin was separated into five molecular weight subpopulations by exclusion chromatography on Bio-Gel A-5m. These subpopulations were compared by amino acid analysis, ultraviolet absorption analysis, fluorescence, far- and near-ultraviolet circular dichroism, isoelectric focusing, SDS-polyacrylamide gel electrophoresis and sedimentation velocity analysis. Although only minor differences were detectable in most physicochemical properties, progressive changes were found in the near-ultraviolet circular dichroism spectra and in pellet hardness after centrifugation. Minute amounts of beta-crystallin polypeptides and a 43 kDa component were present in all five subpopulations. In addition, the highest molecular weight aggregates contain some gamma-crystallin polypeptides. A slow re-equilibration of separated subpopulations towards the initial distribution was observed by rechromatography.
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PMID:Physicochemical characterization of high-molecular-weight alpha-crystallin subpopulations from the calf lens nucleus. 666 39


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