Thesis (PH. D.)--University of Michigan, 1937. / Caption title: Comparative studies of the metabolism of the amino acids. VII. Experimental alcaptonuria in the white rat, by Evangeline Papageorge and Howard B. Lewis. "Reprinted from the Journal of biological chemistry, vol. 123, no. 1 ... 1938." eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 219-220.

In this study, M06-2X/6-311+G(2d,2p) level calculations were performed to examine the binding energies and vibrational frequencies of different conformers of phenylalanine dipeptide interacting with metal ions (Na+, K+, Mg2+ and Ca2+). Four conformers were selected from the list of 20 most stable structures. The main goal was to understand the influence of conformers on the binding affinity of metal ions with different conformers of phenylalanine dipeptide. In agreement with experimental results, interactions of metal ions with two aromatic rings along with lone pair electrons of oxygen produced high stability. Binding energy was lowest for the metal ion interacting with only one aromatic ring. This study revealed the binding affinity order of metal ions Mg2+ > Ca2+ > Na+ > K+ with any of the conformers considered for phenylalanine dipeptide.

This thesis investigates the potential for monitoring current and historic blood serum concentrations of amino acids via transdermal extraction using phenylalanine as a case study. This work furthers the field of non-invasive monitoring of amino acid disorders which have several advantages over invasive methods such as blood tests. In this thesis we derive models to simulate blood serum concentrations, the formation of the skin reservoir and, finally, transdermal extraction of amino acids under an applied electric field. Chapter 1 concerns itself with the biological background and sets up motivation of the thesis by discussing amino acids, associated amino acid disorders, the overarching clinical problem, skin structure and transdermal extraction methods. Chapter 2 then considers mathematical techniques utilised throughout the thesis. Chapter 3 formulates a model for the distribution of phenylalanine in blood serum. One compartment and two compartment approaches are considered in both a fasting state and a non-fasting state. We consider if these have a noticeable effect on the blood serum concentration of phenylalanine. Having obtained a model for the distribution of phenylalanine in blood serum, chapter 4 models the formation of reservoirs of amino acids in the skin. Prior work has identified the existence of such a reservoir, but its formation has not been addressed. The models developed consider the effect of the removal of outer layers of skin, the stratum disjunctum, and production of amino acids in the skin. Unknown parameters are estimated by comparing the model to in vivo and in vitro data. Chapter 5 and 6 are concerned with transdermal extraction under an applied electric field. Chapter 5 formulates the velocity induced by applying an electric field across a charged interface. Chapter 6 utilises these results for modelling extraction of compounds through the skin under an applied electric field.

Phenylketonuria and hyperphenylalanemia are autosomal recessive inborn errors of phenylalanine metabolism that are caused by mutations in the phenylalanine hydroxylase gene. Due to the stringency of the present dietary therapy, alternative treatments are being studied. Phenylalanine ammonia-lyase (PAL) is one of the potential dietary supplements for these patients. PAL is a well-studied plant enzyme which breaks down phenylalanine into trans-cinnamic acid and ammonia (Camm and Towers, 1973). It is found in the cytoplasm of the plant cells and is naturally encapsulated by plant cell walls which may protect it against the acidic pH environment in the gastrointestinal tract. It presumably degrades ingested Phe that circulates in the intestinal lumen. In this study, red spring wheat seedlings (Triticum aestivum L.) found to contain high PAL activity naturally were investigated as a potential alternative oral therapy. Specifically, the objectives were (1) to evaluate different drying methods on generating concentrated and dried preparation of wheat seedlings containing high levels of PAL activity; (2) to examine the retention of PAL activity over three months of storage under various storage conditions; (3) to determine the stability of PAL activity in simulated human digestion condition to establish if further study of using plant source enzyme in vivo is warranted. Freeze-drying (FD) was found to have retained the most activity (>90 % recovery dry wt basis) compared to air-drying (AD) and vacuum-microwave drying (VMD) for both leaf and residual seed/root samples. Pre-freezing of leaf tissues at -18 °C before FD significantly retained the highest PAL activity compared to pre-freezing at -25 °C, -35 °C, and -80 °C (P<0.05). Over three months of storage, 60-80 % of PAL activity was recovered in leaf and —100 % was recovered in residual seed/root tissues after storage at -20 °C. After in vitro protein digestion, 36% and 42 % of PAL activity was recovered in fresh leaf and root tissues respectively; however, FD tissues were found to be susceptible to proteases and acidic environment and no activity was recovered after three hours of in vitro protein digestion. High performance liquid chromatography (HPLC) analysis of the residual Phe after in vitro protein digestion confirmed that fresh tissues had significantly higher conversion of Phe than that of FD tissues. Together, these results suggest that red spring wheat seedlings may have potential as a dietary supplement for phenylketonuric patients while further study to enhance PAL activity in plant preparations is required.

Phenylketonuria and hyperphenylalanemia are autosomal recessive inborn errors of phenylalanine metabolism that are caused by mutations in the phenylalanine hydroxylase gene. Due to the stringency of the present dietary therapy, alternative treatments are being studied. Phenylalanine ammonia-lyase (PAL) is one of the potential dietary supplements for these patients. PAL is a well-studied plant enzyme which breaks down phenylalanine into trans-cinnamic acid and ammonia (Camm and Towers, 1973). It is found in the cytoplasm of the plant cells and is naturally encapsulated by plant cell walls which may protect it against the acidic pH environment in the gastrointestinal tract. It presumably degrades ingested Phe that circulates in the intestinal lumen. In this study, red spring wheat seedlings (Triticum aestivum L.) found to contain high PAL activity naturally were investigated as a potential alternative oral therapy. Specifically, the objectives were (1) to evaluate different drying methods on generating concentrated and dried preparation of wheat seedlings containing high levels of PAL activity; (2) to examine the retention of PAL activity over three months of storage under various storage conditions; (3) to determine the stability of PAL activity in simulated human digestion condition to establish if further study of using plant source enzyme in vivo is warranted. Freeze-drying (FD) was found to have retained the most activity (>90 % recovery dry wt basis) compared to air-drying (AD) and vacuum-microwave drying (VMD) for both leaf and residual seed/root samples. Pre-freezing of leaf tissues at -18 °C before FD significantly retained the highest PAL activity compared to pre-freezing at -25 °C, -35 °C, and -80 °C (P<0.05). Over three months of storage, 60-80 % of PAL activity was recovered in leaf and —100 % was recovered in residual seed/root tissues after storage at -20 °C. After in vitro protein digestion, 36% and 42 % of PAL activity was recovered in fresh leaf and root tissues respectively; however, FD tissues were found to be susceptible to proteases and acidic environment and no activity was recovered after three hours of in vitro protein digestion. High performance liquid chromatography (HPLC) analysis of the residual Phe after in vitro protein digestion confirmed that fresh tissues had significantly higher conversion of Phe than that of FD tissues. Together, these results suggest that red spring wheat seedlings may have potential as a dietary supplement for phenylketonuric patients while further study to enhance PAL activity in plant preparations is required.

Thesis (M.S.)--Rochester Institute of Technology, 1990. / Includes bibliographical references, (leaves 108-110).

Thesis (Ph. D.)--University of Michigan, 1930. / Caption title: Comparative studies of the metabolism of the amino acids. V. The oxidation of phenylalanine and phenylpyruvic acid in the organism of the rabbit, by Joseph P. Chandler and Howard B. Lewis. "Reprinted from the journal of biological chemistry, vol. XCVI, no. 3 ... June, 1932." Bibliography: p. 635-636.

Thesis (Ph. D.)--University of Michigan, 1930. / Caption title: Comparative studies of the metabolism of the amino acids. V. The oxidation of phenylalanine and phenylpyruvic acid in the organism of the rabbit, by Joseph P. Chandler and Howard B. Lewis. "Reprinted from the journal of biological chemistry, vol. XCVI, no. 3 ... June, 1932." Bibliography: p. 635-636.

Phenylketonuria and hyperphenylalanemia are autosomal recessive inborn errors of phenylalanine metabolism that are caused by mutations in the phenylalanine hydroxylase gene. Due to the stringency of the present dietary therapy, alternative treatments are being studied. Phenylalanine ammonia-lyase (PAL) is one of the potential dietary supplements for these patients. PAL is a well-studied plant enzyme which breaks down phenylalanine into trans-cinnamic acid and ammonia (Camm and Towers, 1973). It is found in the cytoplasm of the plant cells and is naturally encapsulated by plant cell walls which may protect it against the acidic pH environment in the gastrointestinal tract. It presumably degrades ingested Phe that circulates in the intestinal lumen. In this study, red spring wheat seedlings (Triticum aestivum L.) found to contain high PAL activity naturally were investigated as a potential alternative oral therapy. Specifically, the objectives were (1) to evaluate different drying methods on generating concentrated and dried preparation of wheat seedlings containing high levels of PAL activity; (2) to examine the retention of PAL activity over three months of storage under various storage conditions; (3) to determine the stability of PAL activity in simulated human digestion condition to establish if further study of using plant source enzyme in vivo is warranted. Freeze-drying (FD) was found to have retained the most activity (>90 % recovery dry wt basis) compared to air-drying (AD) and vacuum-microwave drying (VMD) for both leaf and residual seed/root samples. Pre-freezing of leaf tissues at -18 °C before FD significantly retained the highest PAL activity compared to pre-freezing at -25 °C, -35 °C, and -80 °C (P<0.05). Over three months of storage, 60-80 % of PAL activity was recovered in leaf and —100 % was recovered in residual seed/root tissues after storage at -20 °C. After in vitro protein digestion, 36% and 42 % of PAL activity was recovered in fresh leaf and root tissues respectively; however, FD tissues were found to be susceptible to proteases and acidic environment and no activity was recovered after three hours of in vitro protein digestion. High performance liquid chromatography (HPLC) analysis of the residual Phe after in vitro protein digestion confirmed that fresh tissues had significantly higher conversion of Phe than that of FD tissues. Together, these results suggest that red spring wheat seedlings may have potential as a dietary supplement for phenylketonuric patients while further study to enhance PAL activity in plant preparations is required. / Land and Food Systems, Faculty of / Graduate

This study was concerned with setting up a similar situation wherein pregnant mice had an abnormally high phenylalanine metabolism. Through physical and intellectual assessment of their offspring, it would then be possible to determine what effects the abnormal metabolism had during pregnancy and whether or not a restricted diet need be resumed at that time.