Select the TRUE statement about Michealis Constant (Km)

Salient features of Km:- 1. Km value is substrate concentration (expressed in moles/L) at half-maximal velocity 2. It denotes that 50% of enzyme molecules are bound with substrate molecules at that paicular substrate concentration 3. Km is independent of enzyme concentration;If enzyme concentration is doubled, the Vmax will be doubled. But the 1/2 Vmax(Km) will remain exactly the same. 4. Km is the signature of the enzyme. Km value is thus a constant for an enzyme. It is the characteristic feature of a paicular enzyme for a specific substrate 5. The affinity of an enzyme towards its substrate is inversely related to the dissociation constant, Kd for the enzyme-substrate complex Therefore, the smaller the tendency for the dissociation of the complex, the greater is the affinity of the enzyme for the substrate 6. Km denotes the affinity of enzyme for substrate. The lesser the numerical value of Km, the affinity of the enzyme for the substrate is more.