collagen in the medium of three subclones of balb 3t3 a-31 that exhibited contact-inhibition of growth at confluence , as well as in the medium of one that did not , consisted of alpha ( 1 ) and alpha ( 2 ) subunits in the ratio of 3:1 , suggesting that 3t3 cells synthesize type i collagen , [ alpha ( 1 ) ( i ) ] ( 2 ) alpha ( 2 ) , and another type , which we have designated x , composed of alpha ( 1 ) chains , which may or may not be identical to alpha ( 1 ) ( i ) .
C0009325
collagen
C0041455
type i collagen