Biomedical Engineering Reference
In-Depth Information
as the GenBank database, built and distributed by the National Center for Biotech-
nology Information (NCBI) at the National Institutes of Health (http://www.ncbi.
nlm.nih.gov/Genbank/GenbankSearch.html). There are two ways to search the
GenBank database: a text-based query can be submitted through the Entrez system,
or a sequence query can be submitted through the Basic Local Alignment Search
Tool (BLAST) family of programs (see http://www.ncbi.nlm.nih.gov/BLAST/).
BLAST is the most widely used tool for doing sequence searches. One can
either use the Web interface directly or BLAST can be downloaded to a personal
computer and run it locally. The advantages of the Web interface include ease of
use and the fact that the databases are always up to date. The disadvantage of the
Web interface is that large number of searches cannot be done easily. Another data-
base in Europe is the European Molecular Biology Laboratory (EMBL) Nucleotide
Sequence Database (http://www.ebi.ac.uk/embl/).
Starting with a gene sequence, one can determine the protein sequence using
a protein database such as the SWISS-PROT (http://us.expasy.org/sprot/) and the
Entrez Protein Database with strong certainty. Protein sequences can also be com-
pared using a number of methods, their relatedness can be measured, and closely
related proteins can then be assigned families. One could identify or design ligands
that may bind the identified protein and use them for developing a new biosensor
or to develop therapies. For further information on biological databases, genome
analysis, proteome analysis, and the bioinformatics revolution in medicine, refer
to [4].
Problems
9.1
A company has prepared an electrode based on the Quinhydrone solution.
(a) If the company reports a Nernst potential of 59.2 mV at 25
°
C and a pH of
7.0, what is the concentration of the Quinhydrone solution?
(b) The potential of this cell with respect to an Ag/AgCl electrode (contains
a salt bridge concentration of 3.8 M KCl) reference electrode is 202 mV at
25
°
C. Calculate the potential with respect to a SHE.
9.2
A pH electrode is recording a pH of 6.1. Acid added to the solution and the
potential of the pH electrode increases by 177 mV. What is the pH of the new
solution?
9.3
The potential of a half-cell with respect to an SCE reference electrode is:
−
0.793V. Calculate the potential with respect to the cell potential using the
Ag/AgCl (0.014V less negative than SCE).
9.4
FAD is a prosthetic group present in glucose oxidase enzyme. It is reduced to
FADH and the dissociation constant for the reaction is determined to be 25
μ
M at 25
°
C.
(a) What is the potential energy developed at equilibrium?
(b) Is this reaction spontaneous?
(c) If not, what potential will make it spontaneous?
