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.
Because of mutation, a gene can exist in different forms. These alternative forms of a gene are known as alleles. The complete set of alleles contained within an organism is known as its genotype. In asexual organisms, all of the different alleles are linked together evolutionarily. When the organism reproduces, all of the DNA (and all of the alleles are replicated) and pass together, except for those variations introduced by mutation, to their offspring.