In biochemistry, metabolites are often defined as low-molecular-weight, non-peptidic, biogenic compounds that are produced by life processes. Here's a bit more detail on those characteristics:

• Low molecular weight: Most metabolites are much smaller than the macromolecules (like proteins and nucleic acids) that carry out most of the work in our cells. This allows them to easily diffuse across cell membranes and participate in a variety of biochemical reactions.

• Non-peptidic: While some metabolites can be derived from proteins, many are not. This means they're not made up of amino acids, the building blocks of proteins. Metabolites can be made up of a wide variety of chemical structures, including sugars (carbohydrates), lipids (fats), and nucleotides.

• Biogenic: This term refers to substances that are produced by living organisms. This is in contrast to substances that can be found in the environment but are not produced by organisms, like minerals.

• Produced by life processes: Metabolites are the products of metabolism, the vast array of chemical reactions that occur in living cells. These reactions can be divided into two main types: anabolic reactions, which build up complex molecules from simpler ones, and catabolic reactions, which break down complex molecules into simpler ones.

• Normally endogenous and of animal origin: Endogenous metabolites are those that are produced within an organism, tissue, or cell. Metabolites can be of animal origin, but they can also come from plants, fungi, and microorganisms. Some endogenous metabolites, like hormones and neurotransmitters, play critical roles in signaling and regulation.

• Close analogues: This refers to compounds that are structurally similar to natural metabolites. These can include drugs designed to mimic the effects of natural metabolites, as well as substances found in the diet that are metabolized by the body into useful forms.

These metabolites have essential roles in various biological processes, including energy production, cell growth and differentiation, response to environmental changes, and signaling between cells. They also have significant applications in medical and health research, particularly in the area of personalized medicine and disease diagnosis.