three isozyme variants of catechol oxidase have been shown to be determined by alleles of a gene , cx , which has been located on chromosome 10 less than 0.1 recombination units from the endosperm marker du ( 1 ) .-the extractable form of the enzyme is modified by an endogeneous `` '' modifier '' '' which appears to function as an enzyme substrate .
C0022173
isozyme
C0014442
enzyme