Which statements about allosteric enzymes are true?
1. exhibit cooperativity in substrate binding (homoallostery)
2. exhibit regulation of their activity by other, effector molecules (heteroallostery)
3. there is no difference in the binding curve for a cooperative binding versus noncooperative binding enzyme
4. are frequently multisubunit proteins, with multiple active sites view available hint(s)
a. all statements are true.
b. 1 and 4
c. 1 and 2
d. 1, 2, and 4

1,2 and 4 are correct

Explanation:

Enzymes that show cooperativity are defined as Allosteric enzymes. This cooperativity is of several types.

1) homotropic/homoallestery - positive cooperation

2) heterotropic/heteroallestery - negative cooperation

Activity of allosteric enzymes is regulated by other molecules (effector molecules)

Hence, statement 1 and 2 are correct.

Binding curve of allosteric enzymes:

For cooperative binding, binding curve is Sigmoidal curve

For non cooperative binding, binding curve is Hyperboilc curve.

Hence, statement 3 is wrong.

Allosteric enzymes have multiple active sites.

Allosteric enzymes are often multi sub unit proteins.

Hence, statement 4 is correct.

level 4 to level 2 : ))