At high temperatures,enzymes become .........

Basically how many types of enzymes have been recognised by the International Union of Biochemistry?

Under which conditions do metabolic reactions generally occur at a slower rate?

Enzymes are sensitive to .....

Enzymes are proteins. Proteins are long chains of amino acids linked to each other by peptide bonds. Amino acids have many functional groups in their structure. Many of these functional groups are ionisable. As they are weak acids and bases in chemical nature,this ionisation is influenced by the $pH$ of the solution. For many enzymes,activity is influenced by the surrounding $pH$. This is depicted in the curve below. Explain briefly.

In the modern system of nomenclature,which one of the following enzymes occupies the $1^{st}$ position?