Fractionation factors and activation energies for exchange of the low barrier hydrogen bonding proton in peptidyl trifluoromethyl ketone complexes of chymotrypsin

NMR investigations have been carried out of complexes between bovine chymotrypsin Aα and a series of four peptidyl trifluoromethyl ketones, listed here in order of increasing affinity for chymotrypsin: N-Acetyl-l-Phe-CF3, N-Acetyl-Gly-l-Phe-CF3, N-Acetyl-l-Val-l-Phe-CF3, and N-Acetyl-l-Leu-l-Phe-CF3. The D/H fractionation factors (φ) for the hydrogen in the H-bond between His 57 and Asp 102 (His 57-Hδ1) in these four complexes at 5°C were in the range φ = 0.32–0.43, expected for a low-barrier hydrogen bond. For this series of complexes, measurements also were made of the chemical shifts of His 57-Hɛ1 (δ2,2-dimethylsilapentane-5-sulfonic acid 8.97–9.18), the exchange rate of the His 57-Hδ1 proton with bulk water protons (284–12.4 s−1), and the activation enthalpies for this hydrogen exchange (14.7–19.4 kcal⋅mol−1). It was found that the previously noted correlations between the inhibition constants (Ki 170–1.2 μM) and the chemical shifts of His 57-Hδ1 (δ2,2-dimethylsilapentane-5-sulfonic acid 18.61–18.95) for this series of peptidyl trifluoromethyl ketones with chymotrypsin [Lin, J., Cassidy, C. S. & Frey, P. A. (1998) Biochemistry 37, 11940–11948] could be extended to include the fractionation factors, hydrogen exchange rates, and hydrogen exchange activation enthalpies. The results support the proposal of low barrier hydrogen bond-facilitated general base catalysis in the addition of Ser 195 to the peptidyl carbonyl group of substrates in the mechanism of chymotrypsin-catalyzed peptide hydrolysis. Trends in the enthalpies for hydrogen exchange and the fractionation factors are consistent with a strong, double-minimum or single-well potential hydrogen bond in the strongest complexes. The lifetimes of His 57-Hδ1, which is solvent shielded in these complexes, track the strength of the hydrogen bond. Because these lifetimes are orders of magnitude shorter than those of the complexes themselves, the enzyme must have a pathway for hydrogen exchange at this site that is independent of dissociation of the complexes.

The EMS Crisis of the 1990s: Parallels with the present crisis? CEPS Working Document No. 393, 28 March 2014

The EMS crisis of the 1990s illustrated the importance of a lack of confidence in price or exchange rate stability, whereas the present crisis illustrates the importance of a lack of confidence in fiscal sustainability. Theoretically the difference between the two should be minor since, in terms of the real return to an investor, the loss of purchasing power can be the same when inflation is unexpectedly high, or when the nominal value of government debt is cut in a formal default. Experience has shown, however, that expropriation via a formal default is much more disruptive than via inflation. The paper starts by providing a brief review of the EMS crisis, emphasising that the most interesting period might be the ‘post-EMS’ crisis of 1993-95. It then reviews in section 2 the crisis factors, comparing the EMS crisis to today’s euro crisis. Section 3 outlines the main analytical issue, namely the potential instability of high public debt within and outside a monetary union. Section 4 then compares the pressure on public finance coming from the crises for the case of Italy. Section 5 uses data on ‘foreign currency’ debt to disentangle expectations of devaluation/inflation from expectations of default. Section 6 concludes.

Inflation-Targeting, Flexible Exchange Rates and Macroeconomic Performance since the Great Recession. CEPS Working Document No. 394, March 2014

Has inflation targeting (IT) conferred benefits in terms of economic growth on countries that followed this particular monetary policy strategy during the crisis period 2007-12? This paper answers this question in the affirmative. Countries with an IT monetary regime with flexible exchange rates weathered the crisis much better than countries with other monetary regimes, predominantly countries with fixed exchange rates. Part of this difference in growth performance reflects differences in export performance during the initial years of the crisis, which in turn can be explained by real exchange rate depreciations. However, IT seems also to confer other benefits on the countries above and beyond the effects from currency depreciation.

Le role des politiques monétaires et la convergence macroeconomique sur le développement des systèmes financiers dans les pays du sud de la Méditerranée. = The role of monetary policies and macroeconomic convergence in the development of financial systems in south Mediterranean countries. MEDPRO Technical Report No. 12/April 2012

This MEDPRO Technical Report shows that the monetary and exchange rate policies conducted by central banks in the South Mediterranean region display apparent homogeneity in their operational frameworks, albeit with some specificities and differing degrees of advancement. While central banks state that price stability is their ultimate objective, failures to control interest rates as operational objectives of monetary policy result in monetary authorities resorting to quantitative approaches to monetary policy, meaning that monetary aggregates and credit targets are being used as intermediate targets of monetary policy. An econometric exercise limited to Maghreb countries (Algeria, Morocco, and Tunisia) has been conducted to analyse the potential scenarios of convergence and monetary policy coordination. Given the high structural heterogeneity and the slow pace of real convergence due to weak commercial integration in the Maghreb, results nevertheless show alternative dynamics in the integration of effective nominal exchange rates, as well as a complete convergence dynamic in exchange rate policies. Partial convergence of monetary policies regarding the stabilisation of inflation rates remains an open option for a transitional phase where financial integration is low.

Creating Stability: National Preferences and the Origins of European Monetary System. CES Germany & Europe Working Papers, No. 00.9, December 2000

This essay compares the preferences of France, Italy, and Britain on the creation of the European Monetary System in 1978-1979, especially the Exchange Rate Mechanism, which stabilised nominal exchange rates. My claim is that the different conclusions reached by the governments (France and Italy in, Britain out) cannot be explained by economic circumstances or by interests, and I elaborate an intervening institutional variable which helps explain preferences. Deducing from spatial theory that where decisionmakers `sit' on the left-right spectrum matters to their position on the EMS, I argue that domestic constitutional power-. sharing mechanisms privilege certain actors over others in a predictable and consistent way. Where centrists were in power, the government's decision was to join. Where left or right extremists were privileged, the government's decision was negative. The article measures the centrism of the governments in place at the time, and also reviews the positions taken by the national political parties in and out of government. It is intended to contribute to the growing comparativist literature on the European Union, and to the burgeoning literature on EU-member-state relations.

Essays on International Asset Allocation and Pricing

Thesis (Ph.D.)--University of Washington, 2016-06

DOSY NMR studies of chemical exchange behavior of poly(2-hydroxyethyl methacrylate)

PFG-NMR was used to study the chemical exchange of linear PHEMA having a range of molecular weights with water in DMSO containing varying quantities of water. The aim was to investigate the use of PFG-NMR to study chemical exchange between a polymer with exchangeable protons and a small fast diffusing molecule to provide insight into the conformation adopted by a polymer in solution. The experimental data were simulated closely for the two-site exchange case using the Bloch equations modified for chemical exchange and diffusion. The exchange rate could be used to detect changes in polymer conformation resulting from changes in the solvent. PHEMA of MW 10 000 showed significant time-dependent changes in exchange rate, resulting from preferential solvation of the OH sites by water, and subsequent conformational changes which altered accessibility of the OH sites to water. This behavior was not observed for larger MW PHEMA, which adopted a stable conformation immediately. Large changes in the exchange rate were not reflected in changes to the hydrodynamic radius, suggesting that a minimal overall change in the chain dimensions occurred. DMSO was found to be a poor solvent for PHEMA, which adopts a compact conformation in DMSO. This work has demonstrated that PFG-NMR is a sensitive method for detecting subtle changes in polymer conformation in polymers with exchangeable protons.

Forecasting exchange rates with linear and nonlinear models

In this paper, the exchange rate forecasting performance of neural network models are evaluated against the random walk, autoregressive moving average and generalised autoregressive conditional heteroskedasticity models. There are no guidelines available that can be used to choose the parameters of neural network models and therefore, the parameters are chosen according to what the researcher considers to be the best. Such an approach, however,implies that the risk of making bad decisions is extremely high, which could explain why in many studies, neural network models do not consistently perform better than their time series counterparts. In this paper, through extensive experimentation, the level of subjectivity in building neural network models is considerably reduced and therefore giving them a better chance of Forecasting exchange rates with linear and nonlinear models 415 performing well. The results show that in general, neural network models perform better than the traditionally used time series models in forecasting exchange rates.

Volatility changes in drachma exchange rates

In January 2001 Greece joined the eurozone. The aim of this article is to examine whether an intention to join the eurozone had any impact on exchange rate volatility. We apply the Iterated Cumulative Sum of Squares (ICSS) algorithm of Inclan and Tiao (1994) to a set of Greek drachma exchange rate changes. We find evidence to suggest that the unconditional volatility of the drachma exchange rate against the dollar, British pound, yen, German mark and ECU/Euro was nonstationary, exhibiting a large number of volatility changes prior to European Monetary Union (EMU) membership. We then use a news archive service to identify the events that might have caused exchange rate volatility to shift. We find that devaluation of the drachma increased exchange rate volatility but ERM membership and a commitment to joining the eurozone led to lower volatility. Our findings therefore suggest that a strong commitment to join the eurozone may be sufficient to reduce some exchange rate volatility which has implications for countries intending to join the eurozone in the future.

Forecasting exchange rates with linear and nonlinear models

In this paper the exchange rate forecasting performance of neural network models are evaluated against random walk and a range of time series models. There are no guidelines available that can be used to choose the parameters of neural network models and therefore the parameters are chosen according to what the researcher considers to be the best. Such an approach, however, implies that the risk of making bad decisions is extremely high which could explain why in many studies neural network models do not consistently perform better than their time series counterparts. In this paper through extensive experimentation the level of subjectivity in building neural network models is considerably reduced and therefore giving them a better chance of performing well. Our results show that in general neural network models perform better than traditionally used time series models in forecasting exchange rates.

The microstructure of the foreign exchange market:the determinants of bid-ask spreads in the foreign exchange market

The purpose of this thesis is to shed more light in the FX market microstructure by examining the determinants of bid-ask spread for three currencies pairs, the US dollar/Japanese yen, the British pound/US dollar and the Euro/US dollar in different time zones. I examine the commonality in liquidity with the elaboration of FX market microstructure variables in financial centres across the world (New York, London, Tokyo) based on the quotes of three exchange rate currency pairs over a ten-year period. I use GARCH (1,1) specifications, ICSS algorithm, and vector autoregression analysis to examine the effect of trading activity, exchange rate volatility and inventory holding costs on both quoted and relative spreads. ICSS algorithm results show that intraday spread series are much less volatile compared to the intraday exchange rate series as the number of change points obtained from ICSS algorithm is considerably lower. GARCH (1,1) estimation results of daily and intraday bid-ask spreads, show that the explanatory variables work better when I use higher frequency data (intraday results) however, their explanatory power is significantly lower compared to the results based on the daily sample. This suggests that although daily spreads and intraday spreads have some common determinants there are other factors that determine the behaviour of spreads at high frequencies. VAR results show that there are some differences in the behaviour of the variables at high frequencies compared to the results from the daily sample. A shock in the number of quote revisions has more effect on the spread when short term trading intervals are considered (intra-day) compared to its own shocks. When longer trading intervals are considered (daily) then the shocks in the spread have more effect on the future spread. In other words, trading activity is more informative about the future spread when intra-day trading is considered while past spread is more informative about the future spread when daily trading is considered

The management of foreign exchange exposure on business contracts overseas

This thesis is a piece of applied research. It is the result of a joint project between the University of Aston Interdisciplinary Higher Degrees Scheme and International Aeradio plc (IAL). It considers the structure and organisation of overseas business and the effects that exchange rate movements have on financial performance. It looks in detail at a series of overseas contracts and factors which affect the monitoring and performance of those contracts. From this initial research is developed a series of conceptual models which attempt to capture the effects of foreign exchange rate movements on contract costing, the monitoring of performance on overseas contracts and a measure of company wide exposure. These models are then considered in the context of real IAL generated data and circumstances. The work is finally considered in the context of a survey of other companies with a similar mode of undertaking overseas business with the aim of placing the work in a general context.

Bid-ask spread dynamics in foreign exchange markets

The aim of this paper is to examine the short term dynamics of foreign exchange rate spreads. Using a vector autoregressive model (VAR) we show that most of the variation in the spread comes from the long run dependencies between past and future spreads rather than being caused by changes in inventory, adverse selection, cost of carry or order processing costs. We apply the Integrated Cumulative Sum of Squares (ICSS) algorithm of Inclan and Tiao (1994) to discover how often spread volatility changes. We find that spread volatility shifts are relatively uncommon and shifts in one currency spread tend not to spillover to other currency spreads. © 2013.

Kelet-közép-európai devizaárfolyamok előrejelzése határidős árfolyamok segítségével (Forecasting the exchange rates of three Central-Eastern European currencies with forward exchange rates)

Írásunkban azt vizsgáljuk, hogy a hosszú lejáratú határidős árfolyamok stacionaritását feltételező hibakorrekciós modellek, amelyeknek korábbi számítások szerint - a világ devizapiaci forgalmának mintegy 75 százalékát kitevő fejlett ipari országokra alkalmazva - kitűnő a mintán kívüli előrejelző erejük, hogyan képesek három keletközép- európai ország devizaárfolyamát előrejelezni. A három vizsgálat alá vont deviza (cseh, magyar, lengyel) esetében az eredmények relációnként nagyon eltérnek, és összességében kedvezőtlenebbek, mint a fejlett ipari országokra kapott eredmények, amit a nem teljesen rugalmas árfolyamrezsim, a rendelkezésre álló adatsor rövidsége, az eurózóna-csatlakozáshoz kapcsolódó bizonytalanságok, a devizakockázati és a határidős kamatprémium létezése, továbbá a Balassa-Samuelson-hatás együttes befolyásaként tudunk értelmezni. JEL kód: E43, F31, F47. /===/ This paper studies whether models that assume long-maturity forward exchange rates are stationary (which proved in earlier studies to provide superior forecasting ability when applied to exchange rates of major currencies) are capable of forecasting the Euro exchange rates of three Central-East European currencies (the Czech koruna, Hungarian forint and Polish zloty). The results for the three currencies differ from each other and are generally much worse than those obtained earlier for major currencies. These unfavourable results are attributed to the consequences of managed exchange-rate systems, to the short time series available, to uncertainties related to future Euro-zone entry, to the existence of a foreign exchange and term premium, and to the Balassa–Samuelson effect.

Kamatlábak és árszint kis, nyitott gazdaságban = Interest rates and price levels in a small open economy

A tanulmány azt vizsgálja, hogy a különböző kamatlábaknak milyen hatásai vannak az árszintre, illetve a nominális árakra egy nyitott elsősorban kis, nyitott gazdaságban szabad tőkeáramlás mellett. Míg a zárt gazdaságban csupán a nominális és reálkamatláb megkülönböztetése a lényeges, nyitott gazdaságban a kamatlábak vizsgálatakor meg kell fontolnunk a kamatlábparitás kérdését is. Tisztáznunk kell a reálkamatláb összetevőit, amelyben fontos szerepet kap mind az árfolyam-begyűrűzés (pass-through), mind pedig a kockázati prémium mértéke. A kamatlábhatások vizsgálatakor először azt a mechanizmust elemezzük, amely által a kamatláb befolyásolja a tartós jószágok költségét (explicit vagy implicit bérleti díját). Másodszor az exportszektor termelési döntése és a hazai kamatláb viszonyára vonatkozó mechanizmust vizsgáljuk. Belátjuk, hogy az exportáló szektor döntései függetlenek lehetnek a belföldi kamatlábaktól. Harmadszor bizonyos árazási viselkedéseket tanulmányozunk. Bebizonyítjuk, hogy a kamatláb olyan növelése, ami nem változtat a jelenlegi árfolyamon, árszintnövelő az importőr ország számára. Megfogalmazható az a nézet, hogy ha van is a kamatlábaknak keresleti hatása a zárt gazdaságban, a kis, nyitott gazdaságban ez vélhetőleg sokkal gyengébb. _____ The study examines what effects various interest rates have on the price level and nomi-nal prices in an open (primarily small) economy with free flows of capital. A closed economy calls for a distinction only between nominal and real rates of interest, but in an open economy, questions of interest-rate parity have to be considered as well. It is nec-essary to clarify the factors behind the real interest rate important for price-level pass-through and for the scale of risk premium. Analysis of interest-rate effects begins with the mechanism whereby the interest rate influences the cost of fixed assets (explicit or implicit rents). Secondly, the mechanism behind the relation of export-sector production decisions and domestic interest rates is examined. It emerges that decisions of the export sector are independent of domestic interest rates. Thirdly, certain types of pricing behav-iour are studied. It is shown that a rise in the interest rate that does not alter the present exchange rate is a price-raising factor for the importing country. It can be assumed that if the interest rate has a demand effect in a closed economy, this will presumably be much weaker in a small open economy.