Matrix metalloproteinases (MMPs) are zinc-containing endopeptidases. They degrade proteins by cleavage of peptide bonds. More than twenty MMPs have been identified and are separated into six groups based on their structure and substrate specificity (collagenases, gelatinases, membrane type [MT-MMP], stromelysins, matrilysins, and others).
Confidence votes 164. Alleles are the different forms of a gene. Alleles are corresponding pairs of genes located at specific positions in the chromosomes. Together, alleles determine the genotype. Alleles which determine some aspect of the phenotype, the physical appearance of an organism, are said to be coding alleles.
Concept 3: Different Genes for Different RNAs. There are 4 types of RNA, each encoded by its own type of gene. The genomic DNA contains all the information for the structure and function of an organism. In any cell, only some of the genes are expressed, that is, transcribed into RNA. There are 4 types of RNA, each encoded by its own type of gene: 1  mRNA - Messenger RNA: Encodes amino acid sequence of a polypeptide. 2  tRNA - Transfer RNA: Brings amino acids to ribosomes during translation. 3  rRNA - Ribosomal RNA: With ribosomal proteins, makes up the ribosomes, the organelles that translate the mRNA.