Download Sucrase Mechanism

Chemistry
Session
Session Objectives
1. Enzymes
2. Cofactors
3. Sucrase Mechanism
4. Carboxypeptidase
5. Metabolism
6. DNA and RNA
7. Lipids
8. Hormones and Vitamins
Enzymes
An enzyme is a protein that acts as a catalyst
for a biological reaction.
Most enzymes are specific for substrates while
enzymes involved in digestion such as papain
attack many substrates
Cofactors
In addition to the protein part, many enzymes also have a
nonprotein part called a cofactor
The protein part in such an enzyme is called an apoenzyme,
and the combination of apoenzyme plus cofactor is called a
holoenzyme. Only holoenzymes have biological activity;
neither cofactor nor apoenzyme can catalyze reactions by
themselves
A cofactor can be either an inorganic ion or an organic
molecule, called a coenzyme
Many coenzymes are derived from vitamins, organic
molecules that are dietary requirements for metabolism
and/or growth
Types of Enzymes by Function
Enzymes are usually grouped according to the kind of
reaction they catalyze, not by their structures
How Do Enzymes Work? Citrate Synthase
Citrate synthase catalyzes a mixed Claisen condensation
of acetyl CoA and oxaloacetate to give citrate
Normally Claisen condensation require a strong base in
an alcohol solvent but citrate synthetase operates in
neutral solution
Sucrase Mechanism
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Sucrase Mechanism
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Active Site of Carboxypeptidase
Carboxypeptidase's
The Structure of Citrate Synthase
Determined by X-ray crystallography
Enzyme is very large compared to substrates,
creating a complete environment for the reaction
Aspects of Metabolism
Metabolism.
The life process.
–Catabolism.
• Substances are broken down.
–Anabolism.
• Substances are built up.
Metabolism
• Lipid metabolism.
–Uptake of fats through walls of intestine.
–Glycerol converted to glyceraldehyde-3-phosphate.
–Fatty acids are oxidized by –oxidation.
• Protein metabolism.
–Stomach:
• HCl and pepsin hydrolize 10% of peptide bonds.
–Intestine:
• Trypsin and chymotrypsin cleave peptide fragments further.
Components of DNA and RNA
DNA: Deoxyribonucleic acid.
Chromosomes: Double stranded DNA
rod-like structures.
Genes: Specific locations on chromasomes
that code for specific traits.
RNA: Ribonucleic acid
Contains ribose instead of deoxyribose.
Generally single stranded.
DNA Double Helix
RNA Single Strand
Focus On Protein Synthesis and
the Genetic Code
The genetic code
How triplets of the four
nucleotides
unambiguously specify
20 amino acids, making
it possible to translate
information from a
nucleotide chain to a
sequence of amino acids.
Transcription
How RNA polymerase, guided by base
pairing, synthesizes a single-stranded
mRNA copy of a gene’s DNA template
Protein Synthesis(Translation)
Translation
How base pairing between mRNA and tRNAs directs
the assembly of a polypeptide on the ribosome
DNA Replication
Click here
Lipids
Some Common Fatty Acids
Saponification
Fats and Oils
Both are triglycerides.
–Differ in the nature of the acid components attached.
– Both are colorless, odorless and tasteless
– Flavors and aromas come from organic impurites.
Fats.
–Predominantly saturated fatty acids.
–Normally solid at room temperature
Oils.
–Predominantly unsaturated fatty acids.
–Liquids at room temperature.
Butter
“Calorie-Free” Fats
Phospholipids
Phospholipids
Hormones
Hormones are molecules that transfer information
from one group of cells to a distant tissue or organ.
They are produced by various endocrine glands.
They are classified on the basis of their structure or
site of activity in the cell.
Hormones
Steroids
Adrenal cortical hormones
(corticodes)
Non-Steroids
Sex hormones
Female sex homones
Estrogen
Progestrone
Peptide hormones
(insulin, glucagon)
Male sex hormones
(Androgens)
Amino acid derivatives
(thyroidal hormones)
Miscellaneous
(Prostaglandins, cyokinins)
Vitamins
They are essential dietary factors required by an
organism in minute quantities.
They are essential for life and their absence causes
deficiency diseases.
Vitamins catalyze biological reactions in very low
concentration
Vitamins are designated A,B,C,D,etc. in order of their
discovery. Subgroup vitamins are designated by
number subscript e.g. B1,B2,B6,B12
Classification:
A.Fat soluble
B.Water soluble
Thank you