Component of the ribosome, a large ribonucleoprotein complex responsible for the synthesis of proteins in the cell. The small ribosomal subunit (SSU) binds messenger RNAs (mRNAs) and translates the encoded message by selecting cognate aminoacyl-transfer RNA (tRNA) molecules. The large subunit (LSU) contains the ribosomal catalytic site termed the peptidyl transferase center (PTC), which catalyzes the formation of peptide bonds, thereby polymerizing the amino acids delivered by tRNAs into a polypeptide chain. The nascent polypeptides leave the ribosome through a tunnel in the LSU and interact with protein factors that function in enzymatic processing, targeting, and the membrane insertion of nascent chains at the exit of the ribosomal tunnel. Component of the small ribosomal subunit (SSU). Mature yeast ribosomes consist of a small (40S) and a large (60S) subunit. The 40S small subunit contains 1 molecule of ribosomal RNA (18S rRNA) and 33 different proteins (encoded by 57 genes). The large 60S subunit contains 3 rRNA molecules (25S, 5.8S and 5S rRNA) and 46 different proteins (encoded by 81 genes) (PubMed:9559554, PubMed:22096102). Hydroxylation at Pro-64 affects translation termination efficiency. The stereochemistry of the 3,4-dihydroxyproline has not yet been determined. Present with 3340 molecules/cell in log phase SD medium. There are 2 genes for uS12 in yeast. Belongs to the universal ribosomal protein uS12 family.