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Hydrolase

In biochemistry, a hydrolase or hydrolytic enzyme is a class of enzymes that catalyze the hydrolysis of a chemical bond. For example, an enzyme that catalyzed the following reaction is a hydrolase:

$A-B+H_{2}O\longrightarrow A-OH+B-H$

Enzyme families which classify as hydrolases include:

• Phosphatases - Which act by hydrolyzing products containing phosphorous (ex. ATP + H₂O ⇌ ADP + P via ATP Hydrolysis)
• Esterases - Which act by hydrolyzing ester groups (ex. CH₃COOCH₂CH₃ + H₂O ⇌ CH₃COOH + CH₃CH₂OH)
• Peptidases (Proteases) - Which act by hydrolyzing peptide bonds via proteolysis (ex. HIV protease cleaving Group-specific antigen)
• Glycosidases - Which act by hydrolyzing polysacchirides (ex. Glycoside Hydrolase)

Metallothionein

Metallothionein (MT) is a family of cysteine-rich, low molecular weight (MW ranging from 500 to 14000 Da) proteins. They may be located in both the cytoplasm and the nucleus of the cell. MTs have the capacity to bind both physiological (such as zinc, copper, selenium) and xenobiotic (such as cadmium, mercury, silver, arsenic) heavy metals through the thiol group of its cysteine residues, which represent nearly 30% of its constituent amino acid residues.

Carbonic Anhydrase

Mechanism

Mechanism of the conversion of carbon dioxide and water to bicarbonate

This mechanism is dependent on the pH of the solution. The higher the pH, the higher the activity of the enzyme (due to the ease of the deprotonation step.

A zinc prosthetic group in the enzyme is coordinated in three positions by histidine side-chains. The fourth coordination position is occupied by water, the attached zinc effectively lowers the water's pKa from 15.7 to 7 which generates a hydroxide ion to attack the carbon dioxide. The pH is then lowered by this decrease in pKa, according to Le Chatelier's principle this drives the reaction towards deprotonation. The carbon dioxide molecule then is able to bind to the active site of the enzyme and positioned for optimal interaction.

The hydroxide ion left attached to the zinc is then able to attack the carbonyl of the carbon dioxide effectively converting it to bicarbonate via the nucleophilic attack. The oxygen from the carbon dioxide molecule then is able to form an intermediate bond during this conversion process.

The bicarbonate ion is then released as the enzyme is regenerated with a proton from solution, this enzyme is now ready to facilitate further catalysis of bicarbonate. This quick turnover rate causes the enzyme to be regenerated rather quickly and efficiently, often seen as a kinetically fast process of converting carbon dioxide within blood cells.

Ester Hydrolysis

Mechanisms regarding the hydrolysis of esters under both acidic and basic solution.

Ester hydrolysis under acidic conditions

Ester hydrolysis under basic conditions

Week3 Tasks - Info for Potassium trifluoroacetate

Properties of Potassium trifluoroacetate

• Molecular formula: CF₃COOK
• Molar mass: 152.11 g/mol
• Melting point: 140-142 °C
• Boiling point:
• Solubility in water: 0.1 g/mL

Potassium trifluoroacetate

See Inorganic compound

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Chemical Properties
Molecular Formula	CF3COOK
Molar Mass	152.11 g/mol
Melting Point	140-142 °C
Solubility in Water	0.1 g/mL

$58x^{2}+{\frac {2}{y}}-498+a_{i}$

Jambels/sandbox

Names
IUPAC name Potassium Trifluoroacetate
Identifiers
Properties
Chemical formula	CF3COOK
Molar mass	152.11 g/mol
Density	1.49 g/mL
Melting point	140 °C
Solubility in water	0.1 g/mL
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references