Four of them are classified as type I membrane proteins, MMP-14, MMP-15, MMP-16 and MMP-24, while remaining two (MMP-17 and MMP-25) are attached to the membrane by glycosylphosphatidylinositol molecule.
MMP-17, MMP-24 and MMP-25 were detected in kidneys not involved with tumour process .
To date, there are 28 MMP family members described, including the collagenase subfamily (MMP-1, MMP-8, and MMP-13), the gelatinase subfamily (MMP-2 and MMP-9), the stromelysin subfamily (MMP-3, MMP-10, and MMP11), membrane-associated MMPs (MMP-14, MMP-15, MMP16, MMP-17, MMP-23, MMP-24
, and MMP-25), and other MMPs, all of which possess a Zn ion-dependent endopeptidase activity homologue domain [18-20].
They are classified according to their substrate specificity, sequence similarity, and domain organization into six groups: collagenases (MMP-1, MMP8, MMP-13, and MMP-18), gelatinases (MMP-2, MMP9), stromelysins (MMP-3, MMP-10), matrilysins (MMP7, MMP-26), membrane-type MMPs (MMP-14, MMP-15, MMP-16, MMP-24
, MMP-17, and MMP-25), and other MMPs (MMP-12, MMP-19, MMP-20, MMP-21, MMP-23, MMP-27, and MMP-28) .
MMPs can be divided into 4 main subtypes: collagenases (MMP-1, MMP-8, and MMP13), stromelysins (MMP-3, MMP-10, and MMP-11), gelatinases (MMP-2 and MMP-9), and membrane-type matrix metalloproteinases (MT-MMP, MMP-14, MMP-15, MMP16, MMP-17, MMP-24
, and MMP-25) .
As MMPs pertencem a classe metalo, dependem de zinco para a sua acao catalitica e sao classificadas em cinco grupos: colagenases (MMP-1, MMP-8, MMP-13, MMP-18), gelatinases (MMP-2 e MMP-9), estromalisinas (MMP-3, MMP-10, MMP-11), MMPs tipo membrana (MMP-14, MMP-15, MMP-16, MMP-17, MMP-24
, MMP-25) e outros (MMP-7, MMP-12, MMP-20 e MMP-26) (Tabela 1) (9, 12, 13).
Membrane-type (MT)-MMPs consist of four transmembrane MMPs, MMP-14 (MT1-MMP), MMP-15 (MT2-MMP), MMP-16 (MT3-MMP), and MMP-24
(MT5MMP) and two glycosyl-phosphatidylinositol-anchored MMPs, MMP-17 (MT4-MMP) and MMP-25 (MT6-MMP).