Skeptics often point to so-called bad designs in biochemical systems, such as pseudoenzymes, as a reason to reject intelligent design. Several recent discoveries, however, indicate that pseudoenzymes play a number of critical roles inside the cell. As is often the case, more complete understanding of biochemical structure and function reveals the cell’s elegant chemistry evincing a Creator’s role in bringing life into existence.
The sophisticated designs of biochemical systems convince me that a Creator exists. (See my book The Cell’s Design for a detailed presentation of my argument for a Creator based on biochemical design.)
But many skeptics reject this conclusion because of what they consider to be bad designs in biochemical systems. They argue that clumsy, faulty designs evident in the biological realm (including biochemical systems) don’t comport with the idea that life stems from the work of an all-powerful, all-knowing, all-benevolent Creator. On the other hand, it is expected that unguided evolutionary processes would generate poorly designed systems.
One example of a “poorly designed” biochemical system came to light about a decade ago when the human genome sequence was made available for researchers to study. It turns out that almost every enzyme family encoded in the human genome includes seemingly nonfunctioning members. (Enzymes are proteins that catalyze—or facilitate—chemical reactions in the cell.) Biochemists have dubbed these nonfunctioning enzymes pseudoenzymes.
For example, one very important class of enzymes is the protein kinases. These enzymes regulate the activity of metabolic pathways and other key cellular processes. Yet, of the 518 protein kinases encoded by the human genome, around 10 percent are incapable of transferring phosphate groups to the target substrate—which is the defining catalytic activity of protein kinases. These catalytically compromised pseudoenzymes are referred to specifically as pseudokinases.
Pseudoenzymes are not confined to the human genome; they are found throughout the biological realm. Presumably, they arose as a result of mutations that rendered functional enzymes nonfunctional. Skeptics are quick point to features such as the widespread occurrence of nonfunctioning enzymes as evidence against intelligent design.
However, several recent studies indicate that, although pseudoenzymes do not catalyze chemical reactions, they do play a number of critical roles inside the cell.1 For example, pseudoenzymes help “true” enzymes catalyze reactions by interacting with them, forcing the actual enzyme to adopt the necessary three-dimensional shape for catalysis to occur. Pseudoenzymes also help promote protein-protein interactions, work with receptor proteins to facilitate intracellular communication, and escort proteins from site to site inside the cell. Often, it is the similarity in structure to true enzymes that allows pseudoenzymes to perform their tasks inside the cell.
As is often the case, a more complete understanding of biochemical systems changes opinion about so-called faulty designs. They turn out to be elegant, sophisticated systems worthy of a Creator.
- Mitch Leslie, “‘Dead’ Enzymes Show Signs of Life,” Science 340 (April 5, 2013): 25–27.