**Core Concept**
The Meister cycle, also known as the gamma-glutamyl cycle, is a process involved in the transfer of glutathione, a tripeptide antioxidant, to amino acids and other molecules. This cycle is crucial in the regulation of glutathione levels and its subsequent conjugation with electrophilic compounds, facilitating their excretion.

**Why the Correct Answer is Right**
The Meister cycle involves the sequential action of gamma-glutamyltransferase and gamma-glutamylcyclotransferase enzymes. The gamma-glutamyltransferase enzyme catalyzes the transfer of gamma-glutamyl moiety from glutathione to an amino acid, forming gamma-glutamyl-amino acid and cysteine. The gamma-glutamylcyclotransferase enzyme then catalyzes the conversion of gamma-glutamyl-amino acid into 5-oxoproline and the amino acid. This cycle is essential for the recycling of glutathione and the detoxification of electrophilic compounds.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not directly related to the Meister cycle and does not describe a relevant process.
**Option B:** This option is incorrect because it does not accurately describe the enzymes involved in the Meister cycle.
**Option C:** This option is incorrect because it does not accurately describe the products formed during the Meister cycle.

**Clinical Pearl / High-Yield Fact**
The Meister cycle is an essential mechanism for maintaining glutathione levels in cells and facilitating the detoxification of electrophilic compounds. A deficiency in this cycle can lead to decreased glutathione levels, increasing the risk of oxidative stress and cellular damage.

**Correct Answer:** C. Gamma-glutamyltransferase and gamma-glutamylcyclotransferase.