Now the second type of posttranslational modification is methylation. And methylation is basically the addition of a methyl group onto certain amino acids via the enzyme known as methyl transferase. So methylation usually increases the hydrophobic character of the enzyme. And so those polypeptides that are methylated basically increase their hydrophobic character as well. Now methylation is utilized in a process known as epigenetic regulation which is basically the regulation of gene expression that takes place during the process of transcription. Now let's move on to the third type of posttranslational modification known as glycosylation.