(BQ) he objective of Ebook Electrical machine is to study the devices used in the interconversion of electric and mechanical energy. Emphasis is placed on electromagnetic t rotating machinery, by means of which the bulk of this energy conversion takes place.
Ribose phosphates are either synthesized through the oxidative branch of
the pentose phosphate pathway, or are supplied by nucleoside phosphorylas-es. The two main pentose phosphates, ribose-5-phosphate and ribose-1-phos-phate, are readily interconverted by the action of phosphopentomutase.
Ribose-5-phosphate is the direct precursor of 5-phosphoribosyl-1-pyrophos-phate, for bothde novoand ‘salvage’ synthesis of nucleotides.
Aconitases are iron–sulfur hydrolyases catalysing the interconversion of cit-rate and isocitrate in a wide variety of organisms. Eukaryotic aconitases
have been assigned additional roles, as in the case of the metazoan dual
activity cytosolic aconitase–iron regulatory protein 1 (IRP1). This human
protein was produced in yeast mitochondria to probe IRP1 folding in this
organelle where iron–sulfur synthesis originates.
In vertebrates, multiple microsomal retinol dehydrogenases are involved in
reversible retinol⁄retinal interconversion, thereby controlling retinoid meta-bolism and retinoic acid availability. The physiologic functions of these
enzymes are not, however, fully understood, as each vertebrate form has
several, usually overlapping, biochemical roles.
Studies inknockoutmice support the involvement of alcohol
dehydrogenases ADH1 and ADH4 in retinoid metabolism,
althoughkineticswithretinoids arenotknown for themouse
enzymes.Moreover, a roleof alcohol dehydrogenase (ADH)
in the eye retinoid interconversions cannot be ascertained
due to the lack of information on the kinetics with 11-cis-retinoids. We report here the kinetics of human ADH1B1,
ADH1B2, ADH4, and mouse ADH1 and ADH4 with all-trans-, 7-cis-, 9-cis-, 11-cis- and 13-cis-isomers of retinol and
Phytochromes are photoreceptor proteins that monitor the light environ-ment and regulate a variety of photomorphogenic responses to optimize
the growth and development of plants. Phytochromes comprise N-terminal
photosensory and C-terminal regulatory domains. They are mutually pho-toconvertible between a red-light-absorbing (Pr) and a far-red-light-absorb-ing (Pfr) form. Their interconversion by light stimuli initiates downstream
Halobacterium salinarumdisplays four distinct kinetic forms
of M-intermediate in its bacteriorhodopsin photocycle. In
wild-type, there are mainly two species with time constants
near 2 and 5 ms. Under various kinds of stress, two other
species arise with time constants near 10 and 70 ms. We
show that these four species are interconvertible. Increases
in membrane hydrophobicity convert the slower to faster
forms. Perturbations caused by Triton X-100 or mutations
convert faster to slower forms.
The proton transfer between interconversion tautomers is of importance in synthetic chemistry, such as: keto-enol, imine-enamine, oxime-nitroso [1, 2]…. The keto-enol tautomerization, especially in the -diketone compounds is a common one. Acetyl acetone, one of the -diketone compound, was studied experimentally early and thoroughly [1, 2]. This compound usually exists an equilibrium mixture of enol and keto tautomers with equilibrium
Peptidyl-prolylcis–transisomerases (EC 188.8.131.52) catalyse the
interconversion of cis and trans peptide bonds and are
therefore considered to be important for protein folding.
They are also thought to participate in processes such as
signalling, cell surface recognition, chaperoning and heat-shock response. Here we report the soluble expression of
recombinant Mycobacterium tuberculosispeptidyl-prolyl
investigationof its structure andbiochemical properties....
Bovine seminal ribonuclease (BS-RNase) is the only known
dimeric enzyme characterized by an equilibrium between
two different 3D structures: MxM, with exchange (or
swapping) of the N-terminal 1–20 residues, and M¼M,
without exchange. As a consequence, the hinge region 16–22
has a different tertiary structure in the two forms. In the
native protein, the equilibrium ratio between MxM and
M¼M is about 7 : 3.