Physical Sciences and Mathematics Commons^™

Dipicolinamide Ligands And Analogs For Lanthanides (Ln), Actinides (An) And Mercury (Hg) For Application To Nuclear Fuel Cycle Separations And Waste Management, Ingrid Lehman-Andino

FIU Electronic Theses and Dissertations

Spent nuclear fuel (SNF) – or used nuclear fuel (UNF) – contains long-lived minor actinides such as ²⁴¹Am, ²⁴⁵Cm, and ²³⁷Np, together with fission products that include lanthanides. Minor actinides are responsible for much of the radiotoxicity and heat generation that limits the capacity of geological repositories. Thus, removing minor actinides from UNF can reduce storage time required for decay to natural levels of activity by several orders of magnitude. Actinide(An)/Lanthanide(Ln) separation processes via solvent extraction by selective complexation with organic or aqueous ligands have to overcome difficulties due to similarities in their ionic radii for the …

Use Of Laser Induced Breakdown Spectroscopy For The Detection And Analysis Of Chemical Taggants, Cole Andrew Pajunen

FIU Electronic Theses and Dissertations

Chemical taggants impart a unique imprint on an object so that, if stolen, the ownership or original source of the object can be unambiguously identified. A commercially available tagging system from SmartWater® Technology Ltd. utilizes a polymer-based solution that solidifies upon application and contains a unique combination of up to 27 rare-earth elements as the chemical identification system. Currently, Laser ablation inductively coupled mass spectrometry (LA-ICP-MS) is used as the primary means to determine the presence/absence of these elements. This current study investigates the use of a commercial laser induced breakdown spectroscopy (LIBS) system as an alternative detection method due …

Systematic Comparison Of Pre-Treatment Parameters In Forensic Hair Analysis And Investigating Hair-Drug Interactions, Jennett Chenevert Aijala

FIU Electronic Theses and Dissertations

Forensic toxicological analysis for the purposes of protecting human health and supporting criminal justice activities can be achieved, in part, by means of analysis of human head hair for detection of abused substances. Hair is considered an alternative sample matrix (compared to blood and urine) because of persistent interpretive challenges caused by a lack of standardization in analytical approaches and poor understanding of the biases resulting from physicochemical interactions between major hair components (e.g., melanin) and drugs of abuse. Some of the uncertainty regarding optimal techniques for the pre-treatment of hair specimens results from the unknown nature of the …

Structural Characterization Of Biomolecules Using Tandem Non- Linear And Linear Ion Mobility, Action Spectroscopy, Mass Spectrometry And Molecular Dynamics, Jacob Edward Porter

FIU Electronic Theses and Dissertations

The following thesis comprises the use of novel gas-phase spectroscopic and spectrometric techniques complemented with molecular dynamics for the structural characterization of biomolecules: from small model systems to large proteins. In particular, complementary linear and non-linear ion mobility, mass spectrometry and action spectroscopy has been applied to the separation and characterization of native and kinetic intermediate states of biomolecular ions. This suite of tools, comprising ion mobility in tandem with non-ergodic fragmentation and action spectroscopy, provided unique information on the conformational space, folding and binding dynamics of single stranded DNA, peptides, peptide-cofactor and protein systems. Theoretical modeling provided candidate structures …

Nmr-Based Metabolic Profiles Of Intact Zebrafish Embryos Exposed To Aflatoxin B1 Recapitulates Hepatotoxicity And Supports Possible Neurotoxicity, Zain Zuberi, Muhamed N.H. Eeza, Joerg Matysik, John P. Berry, A. Alia

Department of Chemistry and Biochemistry

Aflatoxin B1 (AFB1) is a widespread contaminant of grains and other agricultural crops and is globally associated with both acute toxicity and carcinogenicity. In the present study, we utilized nuclear magnetic resonance (NMR), and specifically high-resolution magic angle spin (HRMAS) NMR, coupled to the zebrafish (Danio rerio) embryo toxicological model, to characterize metabolic profiles associated with exposure to AFB1. Exposure to AFB1 was associated with dose-dependent acute toxicity (i.e., lethality) and developmental deformities at micromolar (≤ 2 µM) concentrations. Toxicity of AFB1 was stage-dependent and specifically consistent, in this regard, with a role of the liver and phase I enzyme …

Isolation And Characterization Of Potential Neurotoxic Cyanobacterial Metabolites Associated With Intoxication Of Captive Bottlenose Dolphins In The Florida Keys, Christina Lydon

FIU Electronic Theses and Dissertations

Bottlenose dolphins (Tursiops truncatus) living in captivity in the Florida Keys have recently been observed grazing macrophytic algal communities, and particularly, filamentous cyanobacteria, within their enclosures, and subsequently presenting apparent signs of intoxication. Collections of a mixed assemblage of marine filamentous cyanobacteria were morphologically related to the taxonomically complex and toxigenic polyphyletic genus, Lyngbya, sensu lato. Phylogenetic characterization, using 16S rDNA methods, identified an undescribed member of the recently accepted genus Neolyngbya (Oscillatoriales) among Neolyngbya arenicola, and an unknown Oscillatoriacean species within a poorly resolved clade clustering between the genera Limnoraphis and Capilliphycus.

A dual …

Lithological And Geochemical Responses To Abrupt Global And Regional Paleoenvironmental Changes During The Aptian In A Hemipelagic Setting Of The Eastern Iberian Peninsula: A Multi-Proxy Approach, Jander Socorro

FIU Electronic Theses and Dissertations

Intense episodes of environmental perturbations and regionally to globally distributed, oxygen-deprived marine facies characterize the Cretaceous sedimentary record. The Organyà Basin in the Spanish Pyrenees chronicles this period in expanded stratigraphic sequences that enabled high-resolution sampling and detailed analysis of disturbances poorly recorded in more lithologically condensed sections. Here, I present an integrated multi-proxy study aimed at understanding the Basin’s response to changing paleoenvironmental conditions during the early Aptian stage of the Cretaceous.

Results from the El Pui section indicate that large-scale (> 1‰), negative carbon isotope excursions (CIEs) that show no corresponding shifts in local sources of organic matter …

Advanced Oxidation Processes For The Remediation Of Problematic Organophosphorus Compounds And Perfluoroalkyl Substances, A M Abdullah

FIU Electronic Theses and Dissertations

The presence of persistent organic pollutants, including organophosphorus esters (OPEs) and perfluoroalkyl substances (PFASs) in drinking water sources, is a serious threat to the environment and human health. Advanced oxidation processes (AOPs), specifically TiO₂ photocatalysis and sonolysis, were evaluated to degrade these pollutants in water.

The UV/TiO₂ photocatalysis can effectively degrade tris (2-chloroethyl) phosphate (TCEP) to innocuous materials. The degradation follows pseudo-first-order kinetics and consistent with the Langmuir-Hinshelwood model. Intermediate products identified by ³¹P-NMR show sequential oxidation of alkyl chains, ultimately leading to phosphate. Scavenger studies indicate hydroxyl radical (•OH) is the primary species responsible for the …

Molecular Mechanism Of Dream Dimerization And Interactions With A Non-Physiological Ligand Zn2+., Maria D. Santiago Estevez

FIU Electronic Theses and Dissertations

Downstream Regulatory Element Antagonist Modulator (DREAM) belongs to the family of neuronal calcium sensor proteins and it is involved in several processes in the brain.

Zinc has been shown to bind to recoverin, with submillimolar affinity. Based on the high sequence homology between the NCS family, it is proposed that DREAM can also serve as an intracellular target for Zn²⁺. Fluorescence and CD studies confirm that zinc binds to DREAM with a of K_d = 4 µM, triggering changes in the proteins’ tertiary structure.

The calcium association to DREAM leads to the formation of a Ca^{2+ …}

Consequences Of Non-Physiological Ligands Binding To Dream On Its Secondary And Tertiary Structures And Interactions With Intracellular Partners., Samiol Azam

FIU Electronic Theses and Dissertations

Downstream regulatory antagonist modulator (DREAM) is 29 kDa neuronal calcium sensor (NCS) protein which is expressed in the hippocampus of the brain. DREAM is a multifunctional protein which is involved in a wide spectrum of biological processes, including regulation of potassium current in brain, modulation of pain, presenilin-1 processing, regulation of memory and learning. Exposure to toxic metals such as Pb2+ and Cd2+ have been associated with different types of neurodegenerative diseases. However, how these toxic metals induce neurotoxicity remains an active area of research. In this study, utilizing a combination of spectroscopic and calorimetric techniques, we demonstrated binding of …

Topological Markers For Subcellular Chemical Mapping Using Tof-Sims, Anthony Castellanos

FIU Electronic Theses and Dissertations

Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is a powerful mass spectrometry imaging technique that is uniquely suited to the study of small and challenging biological samples. Mass spectrometry imaging permits the simultaneous detection of chemical species without a priori knowledge of a sample. In the present work, the use of endogenous chemical species, three-dimensional dual-beam depth profiling, and multi-modal mass spectrometry approaches are utilized to increase the specificity and reliability of sub-cellular chemical assignments. In addition, the use of these complimentary indicators serve as useful quality controls to ensure optimal preparation of samples for a high-vacuum environment. In the study …

Development Of Microfluidic Paper-Based Analytical Devices For The Detection Of Low Explosives, Kathryn R. Chabaud

FIU Electronic Theses and Dissertations

Incidents of terrorism have been on the rise despite increased government regulation of explosives. These regulations and the internet have made the application of improvised explosive devices (IEDs) such as fireworks and smokeless powders more prevalent. These devices contain low explosives which are easier to acquire than high explosives, which are more closely monitored. Pipe bombs typically contain smokeless powders, which are mostly comprised of energetics such as nitroglycerine (NG) and organic additives such as diphenylamine. Another type of easily obtainable material containing low explosives is pyrotechnics. Pyrotechnics are usually made up of a mixture of inorganic chemical oxidizers and …

Novel Mips-Parabens Based Spe Stationary Phases Characterization And Application, Angela Tartaglia, Abuzar Kbir, Songhul Ulusoy, Halil Ibrahim Ulusoy, Giuseppe Maria Merone, Fabio Savini, Cristian D'Ovidio, Ugo De Grazia, Serena Gabrielli, Fabio Maroni, Pantaleone Bruni, Fausto Croce, Dora Melucci, Kenneth G. Furton, Marcello Locatelli

Department of Chemistry and Biochemistry

In this work, the synthesis, characterization, and application of novel parabens imprinted polymers as highly selective solid-phase extraction (SPE) sorbents have been reported. The imprinted polymers were created using sol–gel molecular imprinting process. All the seven parabens were considered herein in order to check the phase selectivity. By means of a validated HPLC-photodiode array detector (PDA) method all seven parabens were resolved in a single chromatographic run of 25 min. These SPE sorbents, in-house packed in SPE empty cartridges, were first characterized in terms of extraction capability, breakthrough volume, retention volume, hold-up volume, number of theoretical plates, and retention factor. …

Molecular Mass Growth Through Ring Expansion In Polycyclic Aromatic Hydrocarbons Via Radical–Radical Reactions, Long Zhao, Ralf I. Kaiser, Wenchao Lu, Bo Xu, Musahid Ahmed, Alexander N. Morozov, Alexander Mebel, A. Hasan Howlader, Stanislaw F. Wnuk

Department of Chemistry and Biochemistry

Polycyclic aromatic hydrocarbons (PAHs) represent key molecular building blocks leading to carbonaceous nanoparticles identified in combustion systems and extraterrestrial environments. However, the understanding of their formation and growth in these high temperature environments has remained elusive. We present a mechanism through laboratory experiments and computations revealing how the prototype PAH—naphthalene—can be efficiently formed via a rapid 1-indenyl radical—methyl radical reaction. This versatile route converts five- to six-membered rings and provides a detailed view of high temperature mass growth processes that can eventually lead to graphene-type PAHs and two-dimensional nanostructures providing a radical new view about the transformations of carbon in …

Development Of Dna Methylation Markers To Infer Age, Smoking Status And Body Fluid Types For Forensic Application, Hussain J.H. Alghanim

FIU Electronic Theses and Dissertations

In forensic investigations, biological evidences have great potential to place a suspect at the scene of a crime. However, in many cases suspect(s) usually can’t be identified with any local or national databases. In such challenging cases, police need a tool that can provide investigative leads. Thus, different genetic biomarkers including DNA methylation markers have been developed for different phenotypic traits to serve as source of intelligence information to investigators in cases of unknown DNA profiles. In this project, novel sets of DNA methylation markers were developed for the forensic estimation of human age, determining the smoking status and body …

Functionalized Aptamers For Detection Of Small-Molecule Targets, Haixiang Yu

FIU Electronic Theses and Dissertations

Aptamers have recently gained considerable attention for small-molecule detection in diverse applications such as drug identification, medical diagnostics, and environmental monitoring. However, the performance of aptamer-based sensors has been greatly limited by the low target affinity and responsiveness of small-molecule binding aptamers. This dissertation describes several novel aptamer engineering and isolation strategies to remedy this problem. Specifically, we first develop a generally applicable strategy to engineer split aptamers containing two binding domains termed cooperative-binding split aptamers (CBSAs). CBSAs exhibit higher target binding affinity and are far more responsive in terms of target-induced split aptamer assembly compared to single-domain parent split …

A Randomized Cross-Over Trial Comparing The Effect Of Intramuscular Versus Intranasal Naloxone Reversal Of Intravenous Fentanyl On Odor Detection In Working Dogs, Jennifer L. Essler, Paige G. Smith, Danielle Berger, Elizabeth Gregorio, M. Ross Pennington, Amanda Mcguire, Kenneth G. Furton, Cynthia M. Otto

Department of Chemistry and Biochemistry

Fentanyl is a potent opioid used clinically as a pain medication and anesthetic but has recently seen a sharp rise as an illicit street drug. The potency of fentanyl means mucous membrane exposure to a small amount of the drug can expose first responders, including working canines, to accidental overdose. Naloxone, a fast-acting opioid antagonist administered intranasally (IN) or intramuscularly (IM) is currently carried by emergency personnel in the case of accidental exposure in both humans and canines. Despite the fact that law enforcement relies heavily on the olfactory abilities of canine officers, the effects of fentanyl exposure and subsequent …

Frailty, Cognitive Decline, Neurodegenerative Diseases And Nutrition Interventions, Maria Elena Gomez-Gomez, Sara C. Zapico

Department of Chemistry and Biochemistry

Currently the human population is aging faster. This leads to higher dependency rates and the transformation of health and social care to adapt to this aged population. Among the changes developed by this population is frailty. It is defined as a clinically detectable syndrome, related to the aging of multiple physiological systems, which prompts a situation of vulnerability. The etiology of frailty seems to be multifactorial and its pathophysiology is influenced by the interaction of numerous factors. Morley et al. propose four main mechanisms triggering the frailty: atherosclerosis, sarcopenia, cognitive deterioration and malnutrition, with their respective metabolic alterations. Malnutrition is …

Development Of Improved Extraction/Purification Methods And Comprehensive Screening/Confirmation By Lc-Qqq-Ms Analysis For Novel Psychoactive Substances, Ashley N. Kimble

FIU Electronic Theses and Dissertations

The presence of novel psychoactive substances (NPS) in forensic casework poses major difficulties for detection, since there are many structural variations of NPS circulating in the street market. There are currently no comprehensive screening/confirmatory/quantitation methods available that encompass the majority of NPS encountered in forensic toxicology. A major issue faced with developing such a method is that full validation is extremely time consuming. The use of a liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS) method makes the detection of a large number of NPS possible because of high selectivity and sensitivity.

This research included four main tasks: 1) development …

Comprehensive Analysis Of Synthetic Cannabinoids And Metabolites In Oral Fluid By Liquid Chromatography Triple Quadrupole Mass Spectrometry, Carmen T. Mulet

FIU Electronic Theses and Dissertations

According to NIDA, synthetic cannabinoids (SC) include man-made, mind-altering chemicals. Their typically rapid metabolism and instability in biological matrices requires fast analytical methods for detection and confirmation; therefore, the use of oral fluid (OF) matrix is advantageous because collection is fast and non-invasive. The use of liquid chromatography triple quadrupole mass spectrometry (LC-QqQ-MS) and online solid phase extraction (SPE) for sample pretreatment minimizes bias and facilitates low level detection.

This study demonstrates the first use of online SPE for sample pretreatment in the comprehensive analysis of 100 SC and metabolites in OF by LC-QqQ-MS. The method was validated according the …

Uv And Visible Light-Driven Production Of Hydroxyl Radicals By Reduced Forms Of N, F, And P Codoped Titanium Dioxide, A. M. Abdullah, Miguel A. Gracia-Pinilla, Suresh C. Pillai, Kevin E. O'Shea

Department of Chemistry and Biochemistry

The photocatalytic activities of reduced titanium dioxide (TiO₂) materials have been investigated by measuring their ability to produce hydroxyl radicals under UV and visible light irradiation. Degussa P25 TiO₂ was doped with nitrogen (N), fluorine (F), and/or phosphorus (P) and then subjected to surface modification employing a thermo-physicochemical process in the presence of reducing agent sodium borohydride (NaBH₄). The reduced TiO₂ materials were characterized by a number of X-ray, spectroscopic and imaging methods. Surface doping of TiO₂ was employed to modulate the band gap energies into the visible wavelength region for better overlap …

Uv And Visible Light-Driven Production Of Hydroxyl Radicals By Reduced Forms Of N, F, And P Codoped Titanium Dioxide, A. M. Abdullah, Miguel A. Gracia-Pinella, Suresh C. Pillai, Kevin E. O'Shea

Department of Chemistry and Biochemistry

The photocatalytic activities of reduced titanium dioxide (TiO₂) materials have been investigated by measuring their ability to produce hydroxyl radicals under UV and visible light irradiation. Degussa P25 TiO₂ was doped with nitrogen (N), fluorine (F), and/or phosphorus (P) and then subjected to surface modification employing a thermo-physicochemical process in the presence of reducing agent sodium borohydride (NaBH₄). The reduced TiO₂ materials were characterized by a number of X-ray, spectroscopic and imaging methods. Surface doping of TiO₂ was employed to modulate the band gap energies into the visible wavelength region for better overlap …

Label-Free, Visual Detection Of Small Molecules Using Highly Target-Responsive Multimodule Split Aptamer Constructs, Yingping Luo, Haixiang Yu, Obtin Alkhamis, Yingzhu Liu, Xinhui Lou, Boyang Yu, Yi Xiao

Department of Chemistry and Biochemistry

Colorimetric aptamer-based sensors offer a simple means of on-site or point-of-care analyte detection. However, these sensors are largely incapable of achieving naked-eye detection, because of the poor performance of the target-recognition and signal-reporting elements employed. To address this problem, we report a generalizable strategy for engineering novel multimodule split DNA constructs termed "CBSAzymes" that utilize a cooperative binding split aptamer (CBSA) as a highly target-responsive bioreceptor and a new, highly active split DNAzyme as an efficient signal reporter. CBSAzymes consist of two fragments that remain separate in the absence of target, but effectively assemble in the presence of the target …

5′,8-Cyclopurine Lesions In Dna Damage: Chemical, Analytical, Biological, And Diagnostic Significance, Chryssostomos Chatgilialoglu, Carla Ferreri, Nicholas E. Geacintov, Marios G. Krokidis, Yuan Liu, Annalisa Masi, Vladimir Shafirovich, Michael A. Terzidis, Pawlos S. Tsegay

Department of Chemistry and Biochemistry

Purine 5′,8-cyclo-2′-deoxynucleosides (cPu) are tandem-type lesions observed among the DNA purine modifications and identified in mammalian cellular DNA in vivo. These lesions can be present in two diasteroisomeric forms, 5′R and 5′S, for each 2′-deoxyadenosine and 2′-deoxyguanosine moiety. They are generated exclusively by hydroxyl radical attack to 2′-deoxyribose units generating C5′ radicals, followed by cyclization with the C8 position of the purine base. This review describes the main recent achievements in the preparation of the cPu molecular library for analytical and DNA synthesis applications for the studies of the enzymatic recognition and repair mechanisms, their impact on transcription and genetic …

Towards Trigonal Prismatic Hexanuclear Copper Complexes For Catalytic Water Oxidation, David I. Kreiger

FIU Electronic Theses and Dissertations

Our planet is running out of energy resources and traditional renewables are not easily transported nor will be sufficient to cover the void left by fossil fuels. Therefore, a new energy storage system needs to be adopted. The medium with highest energy density that is readily available is hydrogen from water. However, to access hydrogen, water needs to be oxidized and water oxidation catalysts (WOCs) will be required for widespread adoption. In pursuit of WOCs, several hexauclear copper complexes were synthesized and characterized, including the isolation and characterization of a mixed-valent Cu₆ (formally, Cu^II₅Cu^III) …

Phenolate Derivatives Of Octanuclear Iron-Oxo-Pyrazolato Complexes; Enantiomeric Resolution Of T-Symmetry Species, Konstantinos Lazarou

FIU Electronic Theses and Dissertations

Octanuclear ferric complexes involving achiral phenolates of the general formula [Fe₈(μ-O)₄(μ-pz)₁₂(R-C₆H₄O)₄], (R = 4-NO₂, 4-CN, 4-F, 4-Cl, 4-I, 4-CH₃O, and 3-NO₃), where synthesized and characterized by single crystal X-ray crystallography, elemental analysis, ¹H-NMR, UV-Vis, IR, ⁵⁷Fe Mössbauer spectroscopy and electrochemical methods (cyclic and differential pulse voltammetry). Results indicate that the nature of the phenolate substituents allows the fine tuning of the spectroscopic data of the compounds.

Subsequently, this project focused on the resolution of the racemic …

Oil Hydrocarbon Degradation By Caspian Sea Microbial Communities, John I. Miller, Stephen Techtmann, Julian Fortney, Nagissa Mahmoudi, Dominique Joyner, Jiang Liu, Scott Olesen, Eric Alm, Adolfo Fernandez, Piero Gardinali, Nargiz Garajayeva, Faig S. Askerov, Terry C. Hazen

Department of Chemistry and Biochemistry

The Caspian Sea, which is the largest landlocked body of water on the planet, receives substantial annual hydrocarbon input from anthropogenic sources (e.g., industry, agriculture, oil exploration, and extraction) and natural sources (e.g., mud volcanoes and oil seeps). The Caspian Sea also receives substantial amounts of runoff from agricultural and municipal sources, containing nutrients that have caused eutrophication and subsequent hypoxia in the deep, cold waters. The effect of decreasing oxygen saturation and cold temperatures on oil hydrocarbon biodegradation by a microbial community is not well characterized. The purpose of this study was to investigate the effect of oxic and …

Oil Hydrocarbon Degradation By Caspian Sea Microbial Communities, John I. Miller, Stephen Techtmann, Julian Fortney, Nagissa Mahmoudi, Dominique Joyner, Jiang Liu, Scott Olesen, Eric Alm, Adolfo Fernandez, Piero Gardinali, Nargiz Garajayeva, Faig S. Askerov, Terry C. Hazen

Department of Chemistry and Biochemistry

The Caspian Sea, which is the largest landlocked body of water on the planet, receives substantial annual hydrocarbon input from anthropogenic sources (e.g., industry, agriculture, oil exploration, and extraction) and natural sources (e.g., mud volcanoes and oil seeps). The Caspian Sea also receives substantial amounts of runoff from agricultural and municipal sources, containing nutrients that have caused eutrophication and subsequent hypoxia in the deep, cold waters. The effect of decreasing oxygen saturation and cold temperatures on oil hydrocarbon biodegradation by a microbial community is not well characterized. The purpose of this study was to investigate the effect of oxic and …

Amyz1: A Novel Α-Amylase From Marine Bacterium Pontibacillus Sp. Zy With High Activity Toward Raw Starches, Wei Fang, Saisai Xue, Pengjun Deng, Xuecheng Zhang, Xiaotang Wang, Yazhong Xiao, Zemin Fang

Department of Chemistry and Biochemistry

No abstract provided.

Amyz1: A Novel Α-Amylase From Marine Bacterium Pontibacillus Sp. Zy With High Activity Toward Raw Starches, Wei Fang, Saisai Xue, Pengjun Deng, Xuecheng Zhang, Xiaotang Wang, Yazhong Xiao, Zemin Fang

Department of Chemistry and Biochemistry

Background

Starch is an inexpensive and renewable raw material for numerous industrial applications. However, most starch-based products are not cost-efficient due to high-energy input needed in traditional enzymatic starch conversion processes. Therefore, α-amylase with high efficiency to directly hydrolyze high concentration raw starches at a relatively lower temperature will have a profound impact on the efficient application of starch.

Results

A novel raw starch digesting α-amylase (named AmyZ1) was screened and cloned from a deep-sea bacterium Pontibacillus sp. ZY. Phylogenetic analysis showed that AmyZ1 was a member of subfamily 5 of glycoside hydrolase family 13. When expressed in Escherichia coli …