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Rat liver aldehyde dehydrogenase. II. Isolation and characterization of four inducible isozymes
(American Society for Biochemistry and Molecular Biology, 1984-10-10) Lindahl, Ronald; Evces, Susan
The purification and properties of 4 inducible cytosolic rat liver aldehyde dehydrogenase isozymes are described. Based on their behavior during purification and their properties, the activities can be grouped into 2 classes. The isozyme inducible in normal liver by 2,3,7,8-tetrachlorodibenzo-p-dioxin and the tumor-specific isozyme found in hepatocellular carcinomas have apparent molecular weights of 110,000, prefer NADP+ as coenzyme, and preferentially oxidize benzaldehyde-like aromatic aldehydes, but not phenylacetaldehyde. They also have identical pH profiles and responses to effectors. These isozymes differ slightly in isoelectric point and thermal stability. The normal liver phenobarbital-inducible isozyme and the isozyme appearing during the promotion phase of hepatocarcinogenesis appear to be identical. Both have apparent molecular weights of 165,000, are NAD-specific and prefer aliphatic aldehydes. They can oxidize phenylacetaldehyde, but not benzaldehyde-like aromatic aldehydes. They also have identical pH and thermal stability profiles and responses to effectors. While the 4 inducible isozymes share identical subunit molecular weights (54,000) with the normal liver millimolar Km aldehyde dehydrogenases, they are distinctly different enzymatic species. The interrelationships of the various normal liver and inducible rat liver aldehyde dehydrogenases are discussed.
Rat liver aldehyde dehydrogenase. I. Isolation and characterization of four high Km normal liver isozymes.
(American Society for Biochemistry and Molecular Biology, 1984-10-10) Lindahl, Ronald; Evces, Susan
From normal rat liver mitochondrial and microsomal fractions, 4 distinct aldehyde dehydrogenase isozymes with millimolar substrate Km values have been purified and characterized. Two isozymes were isolated from mitochondria and 2 from microsomes. A mitochondrial aldehyde dehydrogenase with a substrate Km in the micromolar range was also identified. Subunit molecular weights for all millimolar Km isozymes is 54,000. The mitochondrial and microsomal millimolar Km isozymes are clearly distinguishable from each other by substrate and coenzyme specificity, pH velocity profiles, and thermal stability. By these same properties, the 2 isozymes from each organelle are virtually identical. The 2 mitochondrial isozymes can be distinguished by apparent molecular weight (I, 170,000; II, approximately 250,000), Km for NADP+, effect of inhibitors, and pI. The 2 microsomal isozymes are of the same apparent molecular weight (approximately 250,000), but are distinguishable by their Km values for benzaldehyde and NADP+, response to inhibitors, and pI.
Second Stage Short Run (X,vc) and (X,sc) Control Charts
(Foundation for Open Access Statistics, 2004-03-23) Elam, Matthew E.; Case, Kenneth E.; Kim, Jong-Min
In their 1970 paper titled "Mean and Variance Control Chart Limits Based on a Small Number of Subgroups" (Journal of Quality Technology, Volume 2, Number 1, pp. 9-16), Yang and Hillier originally derived equations for calculating the factors required to determine second stage short run control limits for ) v,Xc( and )s ,X(c charts. Two issues have restricted the applicability of this particular control chart methodology. These are the limited tabulated values of factors Yang and Hillier present and no example to illustrate the use of the methodology. This paper addresses the first issue by presenting a computer program that accurately calculates the factors regardless of the values of the required inputs. An example shows how to incorporate the methodology into a two stage short run control charting procedure. The computer program is available at http://program.20m.com.
Directing Sampling Based on Uncertainty Analysis
(Computational Hydraulics Inc., 2003-02-15) Graettinger, Andrew; Supriyasilp, Thanaporn; Durrans, S. Rocky; Pitt, Robert E.
Determining where and what to sample for environmental modeling of receiving waters is becoming increasingly important because the need for improved accuracy in model results conflicts with limited site sampling budgets. A quantitative approach to sampling, entitled Quantitatively Directed Exploration (QDE), provides a mathematical framework for determining the best location to sample, and what parameter should be sampled. QDE employs a first-order Taylor series expansion to estimate the uncertainty or variance in the model results. Uncertainty in input parameters is determined through data extrapolation techniques, specifically multivariate conditional probability, while model sensitivity is calculated by directly coding sensitivity derivatives into a model using ADIFOR 2.0.
Combining these two matrices produces the variance in model results, which in turn is employed to direct sampling. The next sampling location is defined as the point where the variance in model results is the largest. Which input parameter to sample is determined by evaluating the contribution to the total variance produced by each input parameter. The QDE approach is demonstrated on a water quality model where non-point source loading, stream characteristics, and contaminant behavior are uncertain input parameters and concentration is the uncertain model result.
Strengthening Your Proposal: A Strategic Approach to Library One-Time Purchases
(2026-03-03) Daugherty, Alice L.; Wilburn, Emily J.
One-time purchases represent significant investment decisions for libraries. This presentation examines strategic approaches to evaluating these acquisitions, considering factors such as total implementation costs, alignment with institutional mission and curricular needs, vendor stability, and long-term value. Attendees will learn methods for prioritizing library needs and building proposals that clearly demonstrate the purpose behind purchase recommendations to stakeholders and administration.