S. Pereyraalfonso et al., CURRENT TRITON-X-100 TREATMENTS DO NOT ALLOW A COMPLETE PLASMINOGEN-ACTIVATOR EXTRACTION FROM DEVELOPING NERVOUS-TISSUE, Neurochemical research, 20(2), 1995, pp. 137-142
Determinations of plaminogen activator (PA) activity are usually perfo
rmed in Triton X-100-treated tissue homogenates or crude membrane frac
tions. Such preparations usually involve a single Triton X-100 treatme
nt. in the present paper we describe the pattern of variability of PA
activity measured in different fractions obtained from the developing
chick CNS by a repetitive procedure of Triton X-100 treatment and ultr
acentrifugation. To further characterize this PA activity we have also
performed zymographic analyses during the embryonic development and t
he early postnatal life. Our results show that: a) a single Triton X-1
00 treatment does not completely extract the enzyme and this lead to a
n underestimation of the total PA activity; b) the PA activity is asso
ciated with the particulate component of the total tissue homogenate r
equiring its complete solubilization more drastic Triton X-100 treatme
nts; c) better estimations of total and specific activities are obtain
ed by using soluble fractions derived by ultracentrifugation from Trit
on X-100-treated membrane fractions; d) the developing chick optic lob
e expresses only one kind of PA. molecule along the entire development
; e) the level of PA activity vary characteristically during the ontog
eny and the early postnatal life indicating the existence of a develop
mentally regulated mechanism of PA expression.