Mammalian sperm are not able to fertilize immediately upon ejaculation; they become fertilization-competent after undergoing changes in the female reproductive tract collectively termed capacitation. Although it has been established that capacitation is associated with an increase in tyrosine phosphorylation, little is known about the role of this event in sperm function. In this work we used a...

This thesis describes a novel approach to the rational design o f artificial esterases and aldolases. The Introduction provides a literature summary of the previous approaches that have been employed towards the design and synthesis of artificial enzyme systems. Chapter 2 describes the preparation and reactivity of a number of polymer based artificial enzymes, which are capable of catalysing es...

We previously cloned cDNAs for all the members (A, B and C) of Xenopus aldolase gene family, and using in vitro transcribed RNAs as references, performed quantitative studies of the expression of three aldolase mRNAs in embryos and adult tissues. A Xenopus egg contains ca. 60 pg aldolase A mRNA and ca. 45 pg aldolase C mRNA, but contains only ca. 1.5 pg aldolase B mRNA. The percent composition ...

Pyridoxal phosphate can act as a specific photosensitizer for amino acid residues in rabbit muscle and spinach leaf aldolases, but the residues affected depend on the pH of the reaction. Below pH 8 one histidine residue per enzyme subunit is destroyed; above pH 8.5 there is little loss of histidine, and photoinactivation is associated with the destruction of specific tyrosine residues, particul...

or ethylenediamune tetrancetate (Type I). Dark grown Euglena and Chlorella have aldolases inhibited by p-ohloromercuribenzoa.te and ethylenediamine tetraacetate but stimulated by K4 (Type II). The red alga, Chondrus, and the golden-brown alga, Ochromonas, appear to possess both types. Bean, pea, and spinach seeds and the leaves and cotyledons of etiolated bean seedlin4s oontain a p-diloromercur...

Understanding enzyme stability and activity in extremophilic organisms is of great biotechnological interest, but many questions are still unsolved. Using 2-deoxy-D-ribose-5-phosphate aldolase (DERA) as model enzyme, we have evaluated structural and functional characteristics of different orthologs from psychrophilic, mesophilic and hyperthermophilic organisms. We present the first crystal stru...

Transaminases have arisen as one of the main biocatalysts for amine production but despite their many advantages, stability is still a concern widespread application. One reasons instability need to use an excess amino donor when trying synthesise amines with unfavourable equilibria. To circumvent this, recycling systems donor, such acid dehydrogenases or aldolases, proved useful push equilibri...