The Company of Biologists

Table 2.

Kinetic constants for transmural ⁶⁵Zn²⁺ transport in the presence and absence of 20 μmol l^–1l-histidine and 50 μmol l^–1 copper

Perfusate	K_m (μmol l^—1)	J_max (pmol cm^—2 min^—1)
Zinc control	267±37	0.07±0.003
Zinc + l-Histidine	310±107	0.13±0.02^{^*}
Zinc + l-Histidine + Cu⁺	119±21^{^†}	0.05±0.002^{^†}
Zinc + l-Histidine + Cu²⁺	2079±1231^{^†}	0.08±0.03^{^†}

Perfusate	K_m (μmol l^—1)	J_max (pmol cm^—2 min^—1)
Zinc control	267±37	0.07±0.003
Zinc + l-Histidine	310±107	0.13±0.02^{^*}
Zinc + l-Histidine + Cu⁺	119±21^{^†}	0.05±0.002^{^†}
Zinc + l-Histidine + Cu²⁺	2079±1231^{^†}	0.08±0.03^{^†}

Values are means ± s.e.m. of three replicates per point.

Significantly different (P<0.01) than control

significantly different (P<0.01) than Zn +l-Histidine treatment