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A Norin

Publications and source records attributed to A Norin.

18 recordsLinked to original sources
PubMed2003

Nicotinoprotein (NAD+ -containing) alcohol dehydrogenase: structural relationships and functional interpretations.

The primary structure of nicotinoprotein alcohol dehydrogenase (ADH) from Amycolatopsis methanolica was determined and used for modelling against known ADH structures, and for evaluation of the coenzyme binding. The results establish the medium-chain dehydrogenase/reductase nature of the nicotinoprotein ADH. Its subunit model and that of the human class Ibeta ADH subunit structure are similar, with mean a carbon deviations of 0.95 A, but they differ in seven loops. Nicotinoprotein ADH occupies a phylogenetic position intermediate between the dimeric and tetrameric ADH families. Two of the differing loops are important for coenzyme binding in the nicotinoprotein model, where one (with a Thr271Arg exchange towards the traditional enzyme) may suggest a slight rotation of the coenzyme adenine ring in the nicotinoprotein, and the other, with an Asn288 insertion, may suggest an extra hydrogen bond to its nicotinamide ribose, favouring stronger binding of the coenzyme. Combined with previous data, this suggests differences in the details of the tight coenzyme binding in different nicotinoproteins, but a common mode for this binding by loop differences.

Actinomycetales↗
PubMed2003

Distinct but parallel evolutionary patterns between alcohol and aldehyde dehydrogenases: addition of fish/human betaine aldehyde dehydrogenase divergence.

Alcohol dehydrogenases (ADHs) of the MDR type (medium-chain dehydrogenases/reductases) have diverged into two evolutionary groups in eukaryotes: a set of 'constant' enzymes (class III) typical of basal enzymes, and a set of 'variable' enzymes (remaining classes) suggesting 'evolving' forms. The variable set has larger overall variability, different segment variability, and variability also in functional segments. Using a major aldehyde dehydrogenase (ALDH) from cod liver and fish ALDHs deduced from the draft genome sequence of Fugu rubripes (Japanese puffer fish), we found that ALDHs form more complex patterns than the ADHs. Nevertheless, ALDHs also group into 'constant' and 'variable' sets, have separate segment variabilities, and distinct functions. Betaine ALDH (class 9 ALDH) is 'constant,' has three segments of variability, all non-functional, and a limited fish/human divergence, reminiscent of the ADH class III pattern. Enzymatic properties of fish betaine ALDH were also determined. Although all ALDH patterns are still not known, overall patterns are related to those of ADH, and group separations may be distinguished. The results can be interpreted functionally, support ALDH isozyme distinctions, and assign properties to the multiplicities of the ADH and ALDH enzymes.

Alcohol Dehydrogenase↗
PubMed1998

Deprivation of leukemia inhibitory factor by its function-blocking antibodies augments T cell activation.

Leukemia inhibitory factor (LIF) is a cytokine that acts on a wide range of cell types in vitro, but knowledge of its physiological role is limited. High levels of LIF protein have been selectively detected in the thymus throughout postnatal development. LIF-deficient mice have shown impaired thymic T cell maturation, suggesting the possibility that T cells require LIF for maturation. We have used highly specific antibodies raised against native rat LIF to inhibit LIF function during a defined and restricted period of thymic T cell maturation (first postnatal week). Surprisingly, we observed increased T cell activation in the LIF-deprived wild-type rat. The increased T cell response is retained even 4 weeks after anti-LIF treatment when the level of LIF in the thymic microenvironment has returned to normal. Our results are in contrast to findings with LIF knockout mice, where decreased T cell activation was observed. These observations suggest that LIF may have alternative effects on various phases of T cell development and that LIF may be involved in the restriction of the T cell repertoire during maturation occurring in the first postnatal week.

Animals↗
PubMed1997

Class 2 aldehyde dehydrogenase. Characterization of the hamster enzyme, sensitive to daidzin and conserved within the family of multiple forms.

Mitochondrial (class 2) hamster aldehyde dehydrogenase has been purified and characterized. Its primary structure has been determined and correlated with the tertiary structure recently established for this class from another species. The protein is found to represent a constant class within a complex family of multiple forms. Variable segments that occur in different species correlate with non-functional segments, in the same manner as in the case of the constant class of alcohol dehydrogenases (class III type) of another protein family, but distinct from the pattern of the corresponding variable enzymes. Hence, in both these protein families, overall variability and segment architectures behave similarly, with at least one 'constant' form in each case, class III in the case of alcohol dehydrogenases, and at least class 2 in the case of aldehyde dehydrogenases.

Aldehyde Dehydrogenase↗
PubMed1997

Mycothiol-dependent formaldehyde dehydrogenase, a prokaryotic medium-chain dehydrogenase/reductase, phylogenetically links different eukaroytic alcohol dehydrogenases--primary structure, conformational modelling and functional correlations.

Prokaryotic mycothiol-dependent formaldehyde dehydrogenase has been structurally characterized by peptide analysis of the 360-residue protein chain and by molecular modelling and functional correlation with the conformational properties of zinc-containing alcohol dehydrogenases. The structure is found to be a divergent medium-chain dehydrogenase/reductase (MDR), at a phylogenetic position intermediate between the cluster of dimeric alcohol dehydrogenases of all classes (including the human forms), and several tetrameric reductases/dehydrogenases. Molecular modelling and functionally important residues suggest a fold of the mycothiol-dependent formaldehyde dehydrogenase related overall to that of MDR alcohol dehydrogenases, with the presence of the catalytic and structural zinc atoms, but otherwise much altered active-site relationships compatible with the different substrate specificity, and an altered loop structure compatible with differences in the quaternary structure. Residues typical of glutathione binding in class-III alcohol dehydrogenase are not present, consistent with that the mycothiol factor is not closely similar to glutathione. The molecular architecture is different from that of the 'constant' alcohol dehydrogenases (of class-III type) and the 'variable' alcohol dehydrogenases (of class-I and class-II types), further supporting the unique structure of mycothiol-dependent formaldehyde dehydrogenase. Borders of internal chain-length differences between this and other MDR enzymes coincide in different combinations, supporting the concept of limited changes in loop regions within this whole family of proteins.

Actinomycetales↗
PubMed1995

Class III alcohol dehydrogenase from Saccharomyces cerevisiae: structural and enzymatic features differ toward the human/mammalian forms in a manner consistent with functional needs in formaldehyde detoxication.

Alcohol dehydrogenase class III (glutathione-dependent formaldehyde dehydrogenase) from Saccharomyces cerevisiae was purified and analyzed structurally and enzymatically. The corresponding gene was also analyzed after cloning from a yeast genome library by screening with a probe prepared through PCR amplification. As with class III alcohol dehydrogenase from other sources, the yeast protein was obtained in two active forms, deduced to reflect different adducts/modifications. Protein analysis established N-terminal and C-terminal positions, showing different and specific patterns in protein start positions between the human/mammalian, yeast, and prokaryotic forms. Km values with formaldehyde differ consistently, being about 10-fold higher in the yeast than the human/mammalian enzymes, but compensated for by similar changes in kcat values. This is compatible with the different functional needs, emphasizing low formaldehyde concentration in the animal cells but efficient formaldehyde elimination in the microorganisms. This supports a general role of the enzyme in formaldehyde detoxication rather than in long-chain alcohol turnover.

Alcohol Dehydrogenase↗
PubMed1995

Pulmonary fibroblast function in an acute lung injury model.

The role of pulmonary fibroblasts (PFBs) in early adult respiratory distress syndrome is poorly understood. To investigate PFB cellular function in acute lung injury, New Zealand rabbits (2 to 3 kg) were given either three daily doses of phorbol myristate acetate (PMA; 65 micrograms/kg, IV), a potent stimulator of oxygen radical formation, or saline (control). On day 4, the lungs were harvested, subjected to enzymatic digestion, and PFBs isolated via serial subculture. Proliferation was assessed via 6-hour pulsed [3H]thymidine incorporation and by creating 5-day growth curves. Confluent PFB cultures were assessed for collagen production and total protein production, as well as interleukin (IL)-1 alpha secretion. Qualitative comparisons using transmission electron micrography were also made. There were no differences between PFBs harvested from control versus PMA-treated animals in terms of growth rates, total protein, and IL-1 alpha production. However, there was a significant difference in collagen production, with the PMA-treated animals' PFBs producing 35% more collagen than controls. Transmission electron micrography revealed PMA fibroblasts to be smaller (two to three times), have more dark staining granules, and have hypertrophied smooth endoplasmic reticulum--all consistent with increased metabolic activity. This suggests that pulmonary fibrosis, a late development in adult respiratory distress syndrome, may be triggered during the acute phase of lung injury. The increase in collagen synthesis is not related to PFB proliferation or the secretion of IL-1 alpha.

Acute Disease↗
PubMed1991

Successful cardiac xenogeneic transplantation in primates using total lymphoid irradiation.

Combined total lymphoid irradiation (TLI) and cyclosporine (CyA) dramatically prolong cardiac xenografts in small animals. In order to evaluate this immunosuppressive regimen in primates, heterotopic cardiac cervical xenografts were implanted in a monkey-to-baboon model. The following groups evolved: group 1 (n = 2) control, no immunosuppression; group 2 (n = 4) CyA and steroids; group 3 (n = 2) preoperative TLI (800 rad total); group 4 (n = 4) TLI combined with CyA and steroids as in groups 2 and 3. Complement-dependent cytotoxicity, mixed lymphocyte culture, cell mediated cytotoxicity as well as myocardial biopsies were periodically monitored. A Muga scan was performed at 1 year posttransplant to assess ventricular function. Cardiac xenograft survival was best in group 4 animals (108, 184, 480, 540 days) compared with 5 and 7 days in the control group. In group 2, graft survival was 13, 17, 18 and 63 days. TLI alone prolonged survival up to 28 and 29 days. Hemorrhage and myocyte necrosis were seen in all rejected grafts of group 1, 2 and 3 animals. Mononuclear cell infiltrate and fibrosis were present in group 4 grafts at rejection. High antibody titers (1:256 to 1:512) were detected at rejection only in group 1, 2 and 3 animals. This suggests that the combined use of TLI and CyA substantially prolongs xenograft survival in a primate model by preventing early antibody-mediated rejection as well as by limiting cellular response.

Animals↗
PubMed1985

Bronchial anastomotic healing in canine lung allotransplants treated with cyclosporine.

Bronchial anastomotic healing was evaluated in 22 long-term-surviving canine lung allotransplant recipients treated with cyclosporine as the major immunosuppressive agent. Mean survival in these dogs was over 155 days, and 4 animals survived 1-3 years. Bronchial anastomotic complications were limited to 5 cases of minimal (less than 15%) bronchostenosis. The bronchial anastomoses became somewhat edematous and friable during rejection episodes, but no clinically serious sequelae--such as hemorrhage, peribronchial abscess, or bronchial dehiscence--were observed. Gross and microscopic evaluation of the recipient and donor segments of the anastomoses revealed excellent healing, with only scattered areas of inflammatory cells. The decreased frequency and severity of rejection episodes in animals treated with cyclosporine permits early revascularization of the bronchus to take place and reduces the need for other immunosuppressive agents that may interfere with bronchial healing. Cyclosporine is an effective immunosuppressive agent for canine lung allotransplantation and allows normal bronchial anastomotic healing to occur.

Animals↗
PubMed1976

DNA excision-repair deficiency of human peripheral blood lymphocytes treated with chemical carcinogens.

Human peripheral blood lymphocytes stimulated with concanavalin A for 72 hr have a 10-fold greater capacity to repair DNA damage induced by N-acetoxy-2-acetylaminofluorene than do unstimulated cells. The increased capacity of concanavalin A-activated cells to repair DNA is not observed after 24 hr in culture, a time at which stimulated cells have not begun to synthesize DNA. The maximum rate of repair synthesis obtained after treatment of stimulated cells with the "large patch"-inducing agent, N-acetoxy-2-acetylaminofluorene, is twice that obtained with methyl methanesulfonate, an agent inducing "small patch" repair. The difference between the maximum rates obtained with N-acetoxy-2-acetylaminofluorene and methyl methanesulfonate is 6-fold in a human lymphoblastoid line. Unstimulated lymphocytes show almost identical rates of repair after treatment with either N-acetoxy-2-acetylaminofluorene or methyl methanesulfonate. There is close correlation between the rate of N-acetoxy-2-acetylaminofluorene-induced repair synthesis and the loss of acetylaminofluorene adducts from DNA. Treatment of lymphocytes with methyl methanesulfonate leads to degradation of cellular DNA with the production of single-stranded regions. Such degradation is not observed with N-acetoxy-2-acetylaminofluroene. We conclude that the rate of excision repair is a function of the capacity of cells for DNA synthesis and that lymphocytes that do not synthesize DNA have a limited repair capacity and cannot be used to distinguish between large and small patch repair.

Acetoxyacetylaminofluorene↗
PubMed1975

The measurement of chemically-induced DNA repair synthesis in human cells by BND-cellulose chromatography.

Repair synthesis in human cells in tissue culture can be readily separated from semi-conservative DNA synthesis with the aid of a benzoylated naphthoylated DEAE cellulose (BND-cellulose) column. Cells are incubated with a radioactive DNA precursor during treatment with a repair-inducing agent. An inhibitor of semi-conservative DNA synthesis (hydroxyurea) is added to slow the progression of the DNA growing point. The cells are lysed and after treatment with ribonuclease and pronase the lysates are sheared and passed through a BND-cellulose column. Native DNA is eluted with I M NaCl. Any increase in radioactivity in the native DNA is due to repair synthesis and the specific repair activity (nucleotides inserted per mug of DNA) can be determined from radioactivity and absorbancy measurements. Repair can also be measured in the region of the DNA growing point by fractionation of the material eluted from BND-cellulose with 50% formamide. Repair was not detected in N-acetoxy-2-acetylaminofluorene (AAAF)-treated lymphoblasts derived from an individual with xeroderma pigmentosum although methyl methanesulfonate (MMS)-induced repair was observed in these cells.

Benz(a)Anthracenes↗