**Core Concept**
Denatured proteins refer to proteins that have undergone a change in their native conformation, typically due to exposure to heat, chemicals, or other stressors. This change disrupts the native secondary, tertiary, and quaternary structures of the protein, leading to a loss of function and potentially affecting its interactions with other molecules.

**Why the Correct Answer is Right**
Denatured proteins exhibit several key characteristics, including increased solubility in water, loss of enzymatic activity, and a change in their overall shape. This is because the bonds that maintain the native conformation of the protein, such as hydrogen bonds and disulfide bridges, are disrupted. As a result, the protein becomes more accessible to other molecules, including enzymes that can break it down.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because denatured proteins can indeed be more soluble in water, as the disruption of hydrophobic interactions allows the protein to interact more freely with water.
* **Option B:** This option is incorrect because denatured proteins typically exhibit a loss of enzymatic activity, not an increase. The disruption of the native conformation prevents the protein from performing its normal function.
* **Option C:** This option is incorrect because denatured proteins often exhibit a change in their overall shape, rather than maintaining their native conformation.

**Clinical Pearl / High-Yield Fact**
Denaturation of proteins can be reversible in some cases, such as with the use of chaperone proteins or changes in temperature. However, irreversible denaturation can lead to the formation of aggregates and the loss of protein function, which can contribute to various diseases, including neurodegenerative disorders.

**Correct Answer:** D