Life Sciences Commons^™

Assessments Of An Exogenous Proteolytic Enzyme In Beef Steer Diets To Improve Growth Performance And Ruminal Fermentation, Juan Manuel Vera

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A series of experiments were conducted to investigate the effects of adding an exogenous proteolytic enzyme (EPE) on growth performance and ruminal fermentation characteristics of beef steers fed growing and finishing diets containing 30% dried distillers grains with solubles (DDGS).

In the first experiment, 48 beef steers were divided into two treatments: DDGS diets with and without EPE. Dry matter intake (DMI) was increased (P = 0.02) by the addition of EPE, but neutral detergent fiber (NDF) digestibility was decreased on the growing phase. For the finishing phase, average daily gain ( …

Characterization Of The Substrate Specificity And Mechanism Of Protein Arginine Methyltransferase 1, Whitney Lyn Wooderchak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Protein arginine methyltransferases (PRMTs) posttranslationally modify protein arginine residues. Type I PRMTs catalyze the formation of monomethylarginine (MMA) and asymmetric dimethylarginine (ADMA) via methyl group transfer from S-adenosyl methionine onto protein arginine residues. Type II PRMTs generate MMA and symmetric dimethylarginine. PRMT-methylation affects many biological processes. Although PRMTs are vital to normal development and function, PRMT-methylation is also linked to cardiovascular disease, stroke, multiple sclerosis, and cancer.

Thus far, nine human PRMT isoforms have been identified with orthologues present in yeast, plants, and fish. PRMT1 predominates, performing an estimated 85% of all protein arginine methylation in vivo. Yet, the substrate …

Purification And Immunological Reactivity Of Commercial Microbial Milk Clotting Enzyme Preparations, Chima I. Osuala

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Commercial microbial milk clotting enzyme preparations were purified by immunoaffinity chromatography using purified antibody covalently coupled to porous glass beads as the column matrix. Commercial enzyme preparation diluted in 1 mM sodium acetate buffer at pH 5.0 was then biospecifically adsorbed to the column matrix by end-over-end mixing of the glass-antibody complex in the enzyme solution for 12 h at 5°C. The antibody bound enzyme adsorbed glass beads were soaked in .2 M glycine or ethanolarnine at pH 7.0 to block uncoupled reactive sites on the matrix. Following this, the column was washed with 1 mM sodium acetate …

Time Course Of Enzyme Catalyzed Reactions: The Stoichiometry A --> P + Q, Tamra Tuttle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The feasibility of using an integrated rate equation to analyze the kinetics of a second-order, enzyme-catalyzed reaction has been investigated. The inducible arginine decarboxylase from Escherichia coli B. was chosen for this study because it catalyzes an irreversible reaction with stoichiometry A --> P + Q, the simplest second order case. Values for five of the eight possible kinetic constants were determined from 21 time courses. Of the remaining three, the uncompetitive product inhibition constant for CO₂ was shown to be between 0 and 0.06, while the values of the competitive product inhibition for CO₂ and the uncompetitive …

A Unified Radiometric Assay System For The Gaba-Glutamate Regulating Enzymes, Robert C. Dinwoodie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this paper was to develop a single assay system for the enzymes which regulate GABA and glutamate concentrations in brain and nerve tissue. Since all the enzymes produce L-glutamate, their activities were measured by coupling them to L-glutamate decarboxylase. Enzymatic activity was determined by measuring the release of co2 from radioactive substrates. The glutamate decarboxylase was obtained from a commercial acetone powder by simplifying existing procedures. The glutamate decarboxylase produced was of sufficient purity to be used in the coupled assays, which were checked with commercial preparations of each enzyme, where available, and with crude brain homogenates. …

Incorporation Of Protoporphyrin Ix Into Chlorophyll A And Purification And Properties Of (-) S-Adenosyl-L-Methionine-Magnesium Protoporphyrin Ix Methyltransferase, Jii Shieh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Experiments on the incorporation of ¹⁴C-protoporphyrin IX into chlorophyll indicate that ferrous iron may be involved in reactions between protoporphyrin IX and chlorophyll. Experiments using both health and chlorotic tobacco tissue for incorporation studies show that incorporation of protoporphyrin IX into chlorophyll was activated by Fe²⁺.

S-adenosylmethionine-magnesium protoporphyrin IX methyltransferase (E.C.2.1.1.11) which catalyzes the reaction between S-adenosylmethionine and Mg protoporphyrin IX to form S-adenosylhomocysteine and Mg protoporphyrin IX monomethyl ester was demonstrated in barley seedlings. Methyltransferase was found principally in whole chloroplasts and fractions containing mitochondria were disintegrated chloroplasts. Use of detergent Tween 80, precipitation with protamine …

Ribose 5'-Phosphate Aminotransferase Of Salmonella Typhimurium, Gulamnabi Y. Vahora

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ribose-5 '-phosphate aminotransferase, an alternate first enzyme in the purine de novo pathway, has been purified about 800-fold from Salmonella typhimurium (pur D-55 ). The enzyme is distinct from ribosylpyrophosphate-5'-phosphate amidotransferase (E C 2.4.2.14), has an approximate molecular weight of 229,000, and requires ribose-5'-phosphate, ATP and either ammonium ion, carbamyl phosphate or L-glutamine, to synthesize 5'-phosphoribosylamine (PRA). A coupled assay system, employing a S. typhimurium (pur G-310) extract as the coupling-agent source, was used to measure the enzyme. PRA production in this system was inhibited by higher ribose-5' -phosphate concentrations and longer (over 10 minutes) incubation periods. It …